💥 Refactor add-hook! macro & change arg order

This update may potentially break your usage of add-hook! if you pass
the :local or :append properties to it. This is how they used to work:

  (add-hook! :append 'some-mode-hook #'do-something)

Thsoe properties must now follow the hooks, e.g.

  (add-hook! 'some-mode-hook :append #'do-something)

Other changes:
- Various add-hook calls have been renamed to add-hook! because I
  incorrectly assumed `defun` always returned its definition's symbol,
  when in fact, its return value is "undefined" (so sayeth the
  documentation). This should fix #1597.
- This update adds the ability to add multiple functions to hooks
  without a list:

    (add-hook! 'some-mode-hook
               #'do-something
               #'do-something-else)

- The indentation logic has been changed so that consecutive function
  symbols at indented at the same level as the first argument, but forms
  are indent like a defun.

    (add-hook! 'some-mode-hook
               #'do-something
               #'do-something-else)

    (add-hook! 'some-mode-hook
      (message "Hello"))

modules/lang/lua/config.el

@@ -26,8 +26,8 @@
   (setq-hook! 'moonscript-mode-hook
     moonscript-indent-offset tab-width)
   (add-hook! 'moonscript-mode-hook
-    #'(+lua|moonscript-fix-single-quotes
-       +lua|moonscript-fontify-interpolation)))
+             #'+lua|moonscript-fix-single-quotes
+             #'+lua|moonscript-fontify-interpolation))
 
 
 ;;