💥 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/editor/fold/config.el

@@ -17,7 +17,7 @@
 ;;
 ;; Packages
 
-(def-package! hideshow ; built-in
+(use-package! hideshow ; built-in
   :commands (hs-toggle-hiding
              hs-hide-block
              hs-hide-level
@@ -62,7 +62,7 @@
            '((t))))))
 
 
-(def-package! evil-vimish-fold
+(use-package! evil-vimish-fold
   :when (featurep! :editor evil)
   :commands (evil-vimish-fold/next-fold evil-vimish-fold/previous-fold
              evil-vimish-fold/delete evil-vimish-fold/delete-all