Refactor pre-commit hooks to use prek (#976)

* ci: change to prek for pre-commit

* refactor: fix shellcheck warnings for the scripts

* chore: unify whitespace formatting

* nix: add prek to dev shell

quickshell/matugen/templates/pywalfox-colors.json

@@ -19,4 +19,4 @@
     "color14": "",
     "color15": "{{colors.on_surface.default.hex}}"
   }
-}
+}