Change signature of tree-sitter font-lock functions

Change signature of tree-sitter font-lock functions

Change from

(START END NODE OVERRIDE &rest _)

to

(NODE OVERRIDE &rest _)

START and END aren't used frequently enough to justify.  If a
fontification function needs them, it can get them from NODE.

* doc/lispref/modes.texi (Parser-based Font Lock): Update manual.

* lisp/progmodes/js.el (js--fontify-template-string)
* lisp/progmodes/python.el (python--treesit-fontify-string)
(python--treesit-fontify-string-end): Change signature.

* lisp/treesit.el (treesit-font-lock-rules): Update docstring.
(treesit-font-lock-fontify-region): Remove START and END arguments.