💥 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/lang/agda/config.el

@@ -4,11 +4,11 @@
   (when (executable-find "agda-mode")
     (file-name-directory (shell-command-to-string "agda-mode locate"))))
 
-(def-package! agda2
+(use-package! agda2
   :when +agda-dir
   :load-path +agda-dir)
 
-(def-package! agda2-mode
+(use-package! agda2-mode
   :defer t
   :config
   (map! :map agda2-mode-map