bug#72116: 30.0.60; Filling c-ts-mode documentation is broken

[Yuan Fu]

> On Jul 14, 2024, at 11:44 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Damien Cassou <damien@cassou.me>
>> Date: Sun, 14 Jul 2024 20:23:09 +0200
>> 
>> Filling documentation in a c-ts-mode buffer doesn't insert the " * "
>> prefix. It works fine in c-mode. How to reproduce:
>> 
>> 1. Install the C treesitter grammar
>> 2. Start emacs with "emacs -Q"
>> 3. Open the attached file in a new buffer
>> 4. Run M-x c-ts-mode
>> 5. Move point to the middle of line 2
>> 6. Press M-q
> 
> You can work around this by enabling auto-fill-mode.  Then typing SPC
> at the end of the long line will produce the effect you want.
> 
> Yuan, can you please look into this?

Fixed and pushed to master. I didn’t push this to emacs-30 since 
adaptive-filling is a fragile being, so let’s wait and see :-)

> 
>> If you remove step 4 from the above instructions, c-mode will do the
>> work just fine.
> 
> In c-mode, M-q is bound to a c-mode specific function, which makes no
> sens in c-ts-mode.  We need a ts-specific solution (and we already
> seem to have it, it just isn't working in this case for some reason).

In c-ts-mode, M-q jumps a few hops, but it eventually calls c-ts-mode’s filling 
function (c-ts-common--fill-paragraph).

Yuan