Fix the range handling in treesit.c
1. In treesit_sync_visible_region, reduce the ranges for a parser so it
doesn't go beyond the visible range.
2. To avoid possible infinite recursion, add a within_reparse field to
parsers. Previously we were using the need_reparse field to avoid
infinite recursion, but lisp programs in a parser's after change hook
might make some buffer edit which turns need_reparse to true. To avoid
that, we now use an explicit field. If a parser's after change function
makes a buffer edit, lisp program ends up with a desynced parse tree,
but that's better than possible infinite recursion. Also after change
function shouldn't edit the buffer.
3. In treesit_make_ranges, use parser's visible_beg instead of buffer's
BEGV. I mean technically whenever we make ranges, buffer's BEGV should
be equal to parser's visible_beg, but better not take that uncertainty,
also makes the code more readable.
4. In Ftreesit_parser_included_ranges, move visible region sync code
before the body of the function.
* src/treesit.c (treesit_sync_visible_region): Minimally fix ranges so
it doesn't exceed parser's visible range.
(treesit_call_after_change_functions): Update calling sigature to
treesit_make_ranges.
(treesit_ensure_parsed, make_treesit_parser): Use the new field
within_reparse.
(treesit_make_ranges): Use parser's visible_beg instead of buffer's
BEGV.
(Ftreesit_parser_included_ranges): Move visible region check before
function body.
* src/treesit.h (Lisp_TS_Parser): Add new field within_reparse.