Add 'restricted' tactic in tree-sitter navigation functions

Add 'restricted' tactic in tree-sitter navigation functions

* lisp/treesit.el (treesit-forward-sexp): Add docstring.  Use
'restricted' tactic.
(treesit-transpose-sexps): Fix docstring.
(treesit-beginning-of-thing)
(treesit-end-of-thing): Add support for TACTIC.
(treesit-beginning-of-defun)
(treesit-end-of-defun): Supply treesit-defun-tactic as TACTIC.
(treesit--navigate-thing): Add support for TACTIC.  Wrap the old form
in a new (if (eq tactic 'restricted) (new-code) (old-form)), and
supply the TACTIC parameter when recursing.