* lisp/progmodes/c-ts-mode.el (c-ts-mode--defun-valid-p)
(c-ts-mode--defun-skipper): New functions.
(c-ts-base-mode): Setup defun navigation.
* lisp/progmodes/sh-script.el (bash-ts-mode): Setup defun navigation.
* lisp/treesit.el (treesit-beginning-of-defun)
(treesit-end-of-defun): Change to new implementation, which is
intended to be used as commands.
(treesit-major-mode-setup): Setup remap for beginning/end-of-defun
commands.