💥 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/doom/config.el

@@ -43,7 +43,7 @@
 (use-package! solaire-mode
   :defer t
   :init
-  (add-hook 'doom-load-theme-hook
+  (add-hook! 'doom-load-theme-hook
     (defun +doom-solaire-mode-swap-bg-maybe-h ()
       (pcase-let ((`(,theme . ,swap) (assq doom-theme +doom-solaire-themes)))
         (require 'solaire-mode)
@@ -53,8 +53,8 @@
   ;; fringe can become unstyled when deleting or focusing frames
   (add-hook 'focus-in-hook #'solaire-mode-reset)
   ;; Prevent color glitches when reloading either DOOM or loading a new theme
-  (add-hook! :append '(doom-load-theme-hook doom-reload-hook)
-    #'solaire-mode-reset)
+  (add-hook! '(doom-load-theme-hook doom-reload-hook) :append
+             #'solaire-mode-reset)
   ;; org-capture takes an org buffer and narrows it. The result is erroneously
   ;; considered an unreal buffer, so solaire-mode must be restored.
   (add-hook 'org-capture-mode-hook #'turn-on-solaire-mode)
@@ -78,7 +78,7 @@
   ;; Because fringes can't be given a buffer-local face, they can look odd, so
   ;; we remove them in the minibuffer and which-key popups (they serve no
   ;; purpose there anyway).
-  (add-hook 'solaire-mode-hook
+  (add-hook! 'solaire-mode-hook
     (defun +doom-disable-fringes-in-minibuffer-h (&rest _)
       (set-window-fringes (minibuffer-window) 0 0 nil)))
 
@@ -88,6 +88,6 @@
     (set-window-fringes (get-buffer-window which-key--buffer) 0 0 nil))
 
   (add-hook! '(minibuffer-setup-hook window-configuration-change-hook)
-    #'+doom-disable-fringes-in-minibuffer-h)
+             #'+doom-disable-fringes-in-minibuffer-h)
 
   (solaire-global-mode +1))