bug#64321: 29.0.92; Tree-Sitter/which-function Narrow/Widen causes modified buffer

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Tue, 27 Jun 2023 21:04:22 -0700
> Cc: 64321@debbugs.gnu.org,
>  Eli Zaretskii <eliz@gnu.org>
> 
> Thanks for the backtrace, it’s very helpful.
> 
> Narrowing and widening are transparent to tree-sitter, so when the buffer 
> widens, from tree-sitter’s POV, text are added to the buffer. Which-func 
> calling the tree-sitter current-defund function ultimately leads to 
> tree-sitter calling treesit—font-lock-notifier which puts text properties on 
> the “added” portion of the buffer, which changed the modified status.
> 
> treesit—font-lock-notifier should put text properties without changing 
> modified status, like what jit-lock does. This patch should fix it.

Thanks.  If this solves the problem, please install in the emacs-29
release branch.