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/niri-colors.kdl

@@ -33,4 +33,4 @@ recent-windows {
         active-color   "{{colors.primary_container.dark.hex}}"
         urgent-color   "{{colors.error.default.hex}}"
     }
-}
+}