doom: Add global general-based shortcut for save buffer

C-SPC f s matches evil based doom shortcut and is more convenient on gpd micro

modules/emacs/doom/config.org

@@ -354,9 +354,13 @@ Customize Modus-themes a little to make it more peppy and vibrant.
 #+begin_src emacs-lisp :lexical t
 (use-package! emacs
   :config
-  (map! :leader (:desc "Enlarge window"
-                 :prefix "w"
-                 :g "o" #'doom/window-enlargen)))
+  (map! :leader
+        (:desc "Enlarge window"
+         :prefix "w"
+         :g "o" #'doom/window-enlargen)
+        (:desc "+file"
+         :prefix "f"
+         :g "s" #'save-buffer)))
 #+end_src
 * Common
 Define global variables that can be used and optionally modified across multiple packages.