bug#63990: 30.0.50; `treesit-install-language-grammar' does not work noninteractively

[Eli Zaretskii]

> From: Dominique Quatravaux <dominique@quatravaux.org>
> Date: Fri, 9 Jun 2023 18:39:05 +0200
> 
> When evaluating the following elisp snippet in the *scratch* buffer,
> 
>     (treesit-install-language-grammar 'bash)
> 
> I expected treesit.el to download and compile the grammar for the bash
> language.
> 
> Instead, I got
> 
> ⛔ Warning (treesit): The installed language grammar for bash cannot be 
> located or has problems
> (not-found): (libtree-sitter-bash.so libtree-sitter-bash.so.0 
> libtree-sitter-bash.so.0.0
> libtree-sitter-bash.dylib libtree-sitter-bash.dylib.0 
> libtree-sitter-bash.dylib.0.0) No such file or directory
> 
> The ~/.emacs.d/tree-sitter directory doesn't even get created,
> indicating that there was in fact no attempt to build or download the library.
> 
> Upon digging down with the debugger, the bug appears to be in
> https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/treesit.el#n3073
> which should read
> 
>                   default-out-dir)))
> 
> instead of
> 
>                   out-dir)))
> 
> Fixing that line as indicated and re-loading the function, fixes the
> problem described above.

Yuan, could you please look into this?