Support alternative range function for tree-sitter range settings

Support alternative range function for tree-sitter range settings

Some embedded parser needs to exclude child nodes from the
range, like markdown-inline.  So I added this keyword that
allows users to customize the range for the embedded parser.
This can also be potentially useful for markdown comments in
rust, for example, because we want to exclude the comment
starters (//) from the embedded markdown parser.

* lisp/treesit.el (treesit-query-range):
(treesit-query-range-by-language): Add new parameter RANGE-FN.
(treesit-range-settings): Add new field RANGE-FN.
(treesit-range-rules): Add new keyword RANGE-FN.
(treesit-range-fn-exclude-children): New function.
(treesit--update-ranges-non-local):
(treesit--update-ranges-local):
(treesit--update-range-1): Support the RANGE-FN field.

(cherry picked from commit 8a3e19f4b39be68c22e056d56adb86397e25a673)