gdscript-mark-defun is missing

[habamax]

There is a remap of C-M-h to gdscript-mark-defun but the function itself is missing.

I remember it worked at some version, I think if the function was intentionally removed the binding should also be removed.

https://github.com/godotengine/emacs-gdscript-mode/blob/8a28276daaa23f10e986367b80dc751c5d26829e/gdscript-mode.el#L67