DOC: stub for convert script

doc/fsl.scripts.fsl_convert_x5.rst

+``fsl.scripts.fsl_convert_x5``
+==============================
+
+.. automodule:: fsl.scripts.fsl_convert_x5
+    :members:
+    :undoc-members:
+    :show-inheritance:

fsl/scripts/fsl_convert_x5.py

@@ -84,7 +84,6 @@ def parseArgs(args):
 
         fname = fslimage.addExt(fname, mustExist=exist)
 
-        # TODO broken
         if fslimage.looksLikeImage(fname):
             return 'nii'
         parser.error('Could not infer format from '