💥 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/editor/snippets/autoload/snippets.el

@@ -256,7 +256,7 @@ shadow the default snippet)."
                                                     +snippets-dir))))))))
 
 ;;;###autoload
-(defun +snippets|show-hints-in-header-line ()
+(defun +snippets-show-hints-in-header-line-h ()
   (setq header-line-format
         (substitute-command-keys
          (concat "\\[yas-load-snippet-buffer-and-close] to finish, "
@@ -268,7 +268,7 @@ shadow the default snippet)."
 ;;; Hooks
 
 ;;;###autoload
-(defun +snippets|enable-project-modes (mode &rest _)
+(defun +snippets-enable-project-modes-h (mode &rest _)
   "Automatically enable snippet libraries for project minor modes defined with
 `def-project-mode!'."
   (if (symbol-value mode)
@@ -276,7 +276,7 @@ shadow the default snippet)."
     (yas-deactivate-extra-mode mode)))
 
 ;;;###autoload
-(defun +snippets|read-only-maybe ()
+(defun +snippets-read-only-maybe-h ()
   "Enable `read-only-mode' if snippet is built-in."
   (when (file-in-directory-p default-directory doom-local-dir)
     (read-only-mode 1)
@@ -287,7 +287,7 @@ shadow the default snippet)."
 ;;; Advice
 
 ;;;###autoload
-(defun +snippets*expand-on-region (orig-fn &optional no-condition)
+(defun +snippets-expand-on-region-a (orig-fn &optional no-condition)
   "Fix off-by-one issue with expanding snippets on an evil visual region, and
 switches to insert mode.