💥 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/ledger/config.el

@@ -20,12 +20,12 @@
       [tab] #'ledger-reconcile-toggle)
 
 
-(def-package! flycheck-ledger
+(use-package! flycheck-ledger
   :when (featurep! :tools flycheck)
   :after ledger-mode)
 
 
-(def-package! evil-ledger
+(use-package! evil-ledger
   :when (featurep! :editor evil +everywhere)
   :hook (ledger-mode . evil-ledger-mode)
   :config