💥 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/ui/nav-flash/config.el

@@ -10,10 +10,11 @@
   :init
   ;; NOTE In :tools lookup `recenter' is hooked to a bunch of jumping
   ;; commands, which will trigger nav-flash.
-  (add-hook!
-    '(imenu-after-jump-hook better-jumper-post-jump-hook
-      counsel-grep-post-action-hook dumb-jump-after-jump-hook)
-    #'+nav-flash-blink-cursor-maybe-h)
+  (add-hook! '(imenu-after-jump-hook
+               better-jumper-post-jump-hook
+               counsel-grep-post-action-hook
+               dumb-jump-after-jump-hook)
+             #'+nav-flash-blink-cursor-maybe-h)
 
   (add-hook 'doom-switch-window-hook #'+nav-flash-blink-cursor-maybe-h)