Some issues with the tree-sitter branch

[Eli Zaretskii]

I noticed several minor issues with the branch while reading the code:

 . Several places assign EMACS_INT values to uint32_t variables with
   an explicit range check (and error signal in case of overflow).
 . Several functions produce Lisp_Object results by reference, and
   callers pass to them pointers to Lisp_Object variables.  Our style
   prefers returning a Lisp_Object value through the return value,
   like this:

      Lisp_Object some_var = some_func (...);

   When a function produces a single value, I think the above is
   preferable.
 . There's a call to malloc in Ftreesit_parser_set_included_ranges
   which doesn't check the return value of malloc, and doesn't signal
   memory-full error when malloc fails (that function should perhaps
   use SAFE_ALLOCA).

In addition, the style of treesit.c (indentation etc.) is not exactly
ours (but this can be fixed later).

Thank you for your work on this important feature.