Single letter Twig function does not appear in Twig reference sidenav

[ker0x]

It seems that the parser has some difficulty to make reference of single letter titles

See the t function for example:

• twig_reference.rst
• twig_reference.html

[OskarStark]

@javiereguiluz can you transfer this issue to docs-builder repo ?

[wouterj]

The underline must at least be 3 characters long.

You can see the t, but it is no title as the underline is only 1 character.

[javiereguiluz]

I can't see the "at least 3 underscore characters" constraint in the official RST spec: https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#sections

So, is this constraint something from our own RST parser and should we fix it?

[wouterj]

Ah indeed, I confused it with the Markdown rules.

Sphinx supports a one length underline, so the Doctrine rst parser is not consistent with it. I just checked the code and it should work with a length of 2.

Personally, given we work on a new parser, I would not invest time in fixing this in the current parser and I would suggest to just use a 2 character underline at the moment. Then in the new parser, I'll make sure it is spec-compliant.

[javiereguiluz]

Fixed in #18361.