💥 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/workspaces/config.el

@@ -83,7 +83,7 @@ stored in `persp-save-dir'.")
                   (display-buffer-in-side-window
                    warnings '((window-height . shrink-window-if-larger-than-buffer)))))))))))
 
-  (add-hook 'persp-mode-hook
+  (add-hook! 'persp-mode-hook
     (defun +workspaces-init-persp-mode-h ()
       (cond (persp-mode
              ;; `uniquify' breaks persp-mode. It renames old buffers, which causes
@@ -109,7 +109,7 @@ stored in `persp-save-dir'.")
   (setq persp-add-buffer-on-find-file nil
         persp-add-buffer-on-after-change-major-mode nil)
 
-  (add-hook 'doom-switch-buffer-hook
+  (add-hook! 'doom-switch-buffer-hook
     (defun +workspaces-add-current-buffer-h ()
       "Add current buffer to focused perspective."
       (when persp-mode