💥 Rename def-package! -> use-package!

Calling this pivotal macro "def-package!" has frequently been a source
of confusion. It is a thin wrapper around use-package, and it should be
obvious that it is so. For this reason, and to match the naming
convention used with other convenience macros/wrappers, it is now
use-package!.

Also changes def-package-hook! -> use-package-hook!

The old macros are now marked obsolete and will be removed when straight
integration is merged.

modules/ui/window-select/config.el

@@ -1,6 +1,6 @@
 ;;; ui/window-select/config.el -*- lexical-binding: t; -*-
 
-(def-package! switch-window
+(use-package! switch-window
   :when (featurep! +switch-window)
   :defer t
   :init
@@ -10,7 +10,7 @@
         switch-window-qwerty-shortcuts '("a" "s" "d" "f" "g" "h" "j" "k" "l")))
 
 
-(def-package! ace-window
+(use-package! ace-window
   :unless (featurep! +switch-window)
   :defer t
   :init
@@ -21,7 +21,7 @@
         aw-background t))
 
 
-(def-package! winum
+(use-package! winum
   :when (featurep! +numbers)
   :after-call (doom-switch-window-hook)
   :config