💥 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/completion/ido/config.el

@@ -41,7 +41,8 @@
      (cl-loop for x in ido-temp-list
               if (char-equal (string-to-char x) ?.)
               collect x)))
-  (add-hook! (ido-make-file-list ido-make-dir-list) #'ido-sort-mtime)
+  (add-hook! '(ido-make-file-list-hook ido-make-dir-list-hook)
+             #'ido-sort-mtime)
 
   ;;
   (ido-mode 1)