💥 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/latex/+ref.el

@@ -5,7 +5,7 @@
         reftex-default-bibliography bibtex-completion-bibliography))
 
 
-(def-package! reftex
+(use-package! reftex
   :hook (LaTeX-mode . reftex-mode)
   :config
   ;; set up completion for citations and references

modules/lang/latex/config.el

@@ -96,7 +96,7 @@ If no viewers are found, `latex-preview-pane' is used.")
     (add-to-list 'LaTeX-indent-environment-list `(,env +latex/LaTeX-indent-item))))
 
 
-(def-package! preview
+(use-package! preview
   :hook (LaTeX-mode . LaTeX-preview-setup)
   :config
   (setq-default preview-scale 1.4
@@ -105,12 +105,12 @@ If no viewers are found, `latex-preview-pane' is used.")
 
 
 ;; Nicely indent lines that have wrapped when visual line mode is activated
-(def-package! adaptive-wrap
+(use-package! adaptive-wrap
   :hook (LaTeX-mode . adaptive-wrap-prefix-mode)
   :init (setq-default adaptive-wrap-extra-indent 0))
 
 
-(def-package! auctex-latexmk
+(use-package! auctex-latexmk
   :when (featurep! +latexmk)
   :after latex
   :init
@@ -123,14 +123,14 @@ If no viewers are found, `latex-preview-pane' is used.")
   (auctex-latexmk-setup))
 
 
-(def-package! company-auctex
+(use-package! company-auctex
   :when (featurep! :completion company)
   :defer t
   :init
   (add-to-list '+latex--company-backends #'company-auctex-environments nil #'eq)
   (add-to-list '+latex--company-backends #'company-auctex-macros nil #'eq))
 
-(def-package! company-math
+(use-package! company-math
   :when (featurep! :completion company)
   :defer t
   :init