An occurrence of `grandchild` was miss-spelled `grand_child` (!).
That caused omission of the `active` class in the link in the nav panel for all grandchildren.

This bug was discovered using `diff` to compare the generated sites built using v0.4.0.rc1 and commit  4396b6b1c836f354bb7aa7edc1a06a49f137d615 on the fix-nav-performance PR branch.

Fixes #396.

Remove inaccurate comments about unpinned gem versions
- pre-release gems have lower precedence than release gems.

Clarify that there aren't yet any changes to `main` since the release of `v0.4.0.rc2`.

prep for v0.4.0.rc2

Fix #863.

The current Liquid code to generate the navigation panel involves the inefficient extraction of a list of pages from a list of page groups (identified by @captn3m0 in his original [explanation of the performance issue](https://github.com/just-the-docs/just-the-docs/issues/863)). 

The optimisation implemented by this PR generates navigation links directly from the list of page groups, thereby avoiding the extraction of a list of pages from it. The Liquid code is now a bit tedious, but I don't see a simpler solution. 

The need for grouping pages arises because Jekyll doesn't provide a filter to sort a list of pages on the value of an arbitrary expression.

Using Jekyll v4.2.2 (macOS 12.5, M2 MacBook Air, 16 GB memory), building https://github.com/endoflife-date/endoflife.date using https://github.com/pdmosses/just-the-docs/blob/fix-nav-performance/_includes/nav.html produced the following profile extract:

Filename                                                    | Count |    Bytes |   Time
------------------------------------------------------------|-------|----------|-------
| just-the-docs-0.4.0.rc1/_layouts/default.html                    |   130 |  3792.04K |  5.160 |
| _includes/nav.html                                               |   130 |  1405.20K |  4.054 |
| just-the-docs-0.4.0.rc1/_includes/head.html                      |   130 |   617.82K |  0.495 |
| _layouts/product.html                                            |   127 |  1014.38K |  0.413 |
| _includes/head_custom.html                                       |   130 |   427.83K |  0.393 |
| assets/js/zzzz-search-data.json                                  |     1 |   149.31K |  0.050 |

@nathancarter has tried adding the new `nav.html` to [a site with over 300 pages](https://nathancarter.github.io/how2data/site/), and reported that it improved the build time of more than 3 minutes to about 30 seconds.

Further optimisation of navigation might be possible (e.g., using [Jekyll include caching](https://github.com/benbalter/jekyll-include-cache)), but the current optimisation should be sufficient for v0.4.0.

To test that this PR does not appear to affect the navigation panel generated by v0.3.3:

1. Clone https://github.com/just-the-docs/just-the-docs-tests.
2. Update `_config.yml` and `Gemfile` to use this PR branch.
3. Run `bundle update`.
4. Inspect the rendering of the entire collection of navigation tests.

(Many of the differences reported in the GitHub visualisation of the changes are due to shifting much of the code 2 spaces to the left, in connection with moving the first `ul` element to be close to its first item.)

Why are these changes being introduced:

* The current tab order requires keyboard or screenreader users to tab
  though all of the navigation links before they get to the main content
  of the page

Relevant ticket(s):

* Discussed as part of larger WCAG ticket https://github.com/just-the-docs/just-the-docs/issues/566

How does this address that need:

* Introduces an off screen link as the first element in the tab order
  that will display when it has focus but remain off screen for users
  not using tab to navigate the document.
* Introduces a new scss file with the required style elements and uses
  colors variables to ensure both light and dark mode are respected.

Background information on this technique:

- https://www.w3.org/TR/WCAG20-TECHS/G1.html
- https://accessibility.oit.ncsu.edu/it-accessibility-at-nc-state/developers/accessibility-handbook/mouse-and-keyboard-events/skip-to-main-content/

This PR updates the home page and the CHANGELOG to refer to  v0.4.0.rc1 as a pre-release or release candidate, rather than a release. See [this comment](https://github.com/just-the-docs/just-the-docs/pull/613#issuecomment-1240442518) for motivation.

It also adds the versioned docs issue (#728) to the roadmap in the CHANGELOG.

As the config for the theme docs now needs to declare callouts, the [callouts docs](https://just-the-docs.github.io/just-the-docs/docs/ui-components/callouts/) can now illustrate the rendered appearance. (These callouts are merely examples: the names and colors should eventually be replaced by a principled collection, taking account of WCAG.)

Follow-up to #613. Relatively self-explanatory!

Co-authored-by: Peter Mosses <18308236+pdmosses@users.noreply.github.com>

The jekyll-asciidoc plugin will take AsciiDoc markup like this:

	.A method that returns the string "Hello, world"
	[example]
	[source,ruby]
	----
	def hello
	  "Hello, world"
	end
	----

And produce HTML like this (syntax highlighting disabled):

	<div class="listingblock">
	  <div class="title">A method that returns the string "Hello, world"</div>
	  <div class="content">
	    <pre class="highlight"><code class="language-ruby" data-lang="ruby">def hello
	  "Hello, world"
	end</code></pre>
	  </div>
	</div>

Previously, because we were applying code block styling to the whole
listingblock, the title would be rendered as normal body text, inside
the code block, which did not look good.  With this change, it will
instead be rendered similarly to a Just The Docs rendered example —
the title will appear where the rendered example usually would.

Co-authored-by: Matt Wang <matt@matthewwang.me>

Adds accessible nav elements for nested pages

Why are these changes being introduced:

* The current links to show/hide the nested pages use a visual only
  svg image with no accessible affordance provided so screenreaders
  will not be able to provide appropriate context for users as to what
  they should expect when clicking these links
* You can see the problem by running a tool like ANDI on the current
  main branch of this repository and then running it again on this
  branch. ANDI shows what a screenreader would read.
* You can also use a tool like Voiceover to hear the importance of what
  this introduces to users that use that technology. Before this change,
  Voiceover would read all of these navigation links as
  "link image just-the-docs" but with this change it will read
  `link image toggle links in <categoryName> category`

Relevant ticket(s):

* This was discussed as part of the larger WCAG compliance ticket
  https://github.com/just-the-docs/just-the-docs/issues/566

How does this address that need:

* This adds an `aria-label` to the link https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-label

Document any side effects to this change:

It appears it might be prefereable to use `aria-labelledby` whenever
possible, but from what I can tell these links are just the visual cue
of the svg with no other affordance given to users to understand what
they'll do so there is nothing to point `aria-labelledby` at.

An `svg` title was considered, but in reading more about it it seemed
like `aria-label` was more appropriate as it puts the label on the `a`
rather than the `svg` which feels more accurate.

* https://developer.mozilla.org/en-US/docs/Web/SVG/Element/title
* https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-labelledby



Co-authored-by: Matt Wang <matt@matthewwang.me>

Building the jekyll site on your own in GitHub workflows fails due missing exclude of `vendor` in `_config.yml`. If someone reuses your `_config.yml` he/she will come across some issues.

Reference: https://github.com/jekyll/jekyll/issues/5267#issuecomment-241379902

Added a missing `{: .no_toc }`, to avoid a 3rd-level item in the displayed TOC at the top of the page.

99% certain we don't use this file;

- [script](https://github.com/just-the-docs/just-the-docs/search?q=script) has no non-`<script>`/doc uses
- [build](https://github.com/just-the-docs/just-the-docs/search?q=build) has no mentions
- we don't need to manually build / package the gem anymore

Bumps [stylelint](https://github.com/stylelint/stylelint) from 14.10.0 to 14.11.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](https://github.com/stylelint/stylelint/compare/14.10.0...14.11.0

)

---
updated-dependencies:
- dependency-name: stylelint
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Short and sweet PR that addresses the follow-up in #909: enabling `mermaid` on our docs site, but making it clear that users still need to opt-in to use it. I've also added an example in-action.

To test: [see the Netlify deploy](https://deploy-preview-935--just-the-docs.netlify.app/docs/ui-components/code/#mermaid-diagram-code-blocks).

Bumps [stylelint-config-standard-scss](https://github.com/stylelint-scss/stylelint-config-standard-scss) from 3.0.0 to 5.0.0.
- [Release notes](https://github.com/stylelint-scss/stylelint-config-standard-scss/releases)
- [Changelog](https://github.com/stylelint-scss/stylelint-config-standard-scss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/stylelint-scss/stylelint-config-standard-scss/compare/v3.0.0...v5.0.0

)

---
updated-dependencies:
- dependency-name: stylelint-config-standard-scss
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Matt Wang <matt@matthewwang.me>

Bumps [stylelint](https://github.com/stylelint/stylelint) from 14.9.1 to 14.10.0.
- [Release notes](https://github.com/stylelint/stylelint/releases)
- [Changelog](https://github.com/stylelint/stylelint/blob/main/CHANGELOG.md)
- [Commits](https://github.com/stylelint/stylelint/compare/14.9.1...14.10.0

)

---
updated-dependencies:
- dependency-name: stylelint
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

A couple of changes to prep for v0.4.0-rc1:

- bump the version
- add myself to the authors + email (this is primarily so that Patrick doesn't get siloed as the only maintainer; if you'd like to be added @just-the-docs/maintainers, let me know!)
- adds some more metadata ([gemspec docs](https://guides.rubygems.org/specification-reference/#metadata))
- updated the path to also include the CHANGELOG and favicon in the gem bundle

Version 0.4.0.rc1 - release PR

`mermaid`: refactor config to use `mermaid_config.js` include, only require `mermaid.version` in `_config.yml` (#909)

This PR has a bit of scope creep! This PR now:

- changes the mermaid opt-in logic to only check for the existence of a `mermaid` key instead of `mermaid != false`: this resolves the follow-up in #857
- changes the behaviour of mermaid configuration
    - instead of using `mermaid_init.html` with default settings, makes the include `mermaid_config.js`
    - the include is loaded directly into the contents of `mermaid_initialize`
    - by default, it is an empty object (i.e. `{}`), triggering the defaults
- updates docs
- adds an example to the markdown kitchen sink  

It does significantly change the interface provided in #857, and I apologize for the confusion. However, given the discussion in this PR, I think it's the best move forward!