Move 'SPC /' to 'SPC s'

/ is harder to reach than s, more so on certain keyboard layouts, so
'SPC /' has been moved to 'SPC s'. Similar has been done to other / and
. leader keybinds. Whats more, 'SPC s' for snippets is seldomly used and
available through other means, so it was removed.

Summary:
- 'SPC /' moved to 'SPC s'
- 'SPC f .' and 'SPC f /' moved to 'SPC f f' and 'SPC f F', respectively
- 'SPC p /' removed (already on 'SPC p f')
- 'SPC p ?' moved to 'SPC p F' (doom/find-file-in-other-projects)
- 'SPC n /' moved to 'SPC n s' (+default/org-notes-search)
- 'SPC n .' removed (already on 'SPC n N')
- Remove 'SPC s' prefix for snippets. Was seldomly used and most of its
  commands are available on other keys or through `M-x`, which is
  enough.

modules/config/default/autoload/default.el

@@ -334,6 +334,14 @@ ARG is set, prompt for a known project to search from."
     (sit-for 1))
   (server-start))
 
+;;;###autoload
+(defun +default/find-file-under-here ()
+  "Perform a recursive file search from the current directory."
+  (interactive)
+  (if (featurep! :completion ivy)
+      (call-interactively #'counsel-file-jump)
+    (λ! (doom-project-find-file default-directory))))
+
 ;;;###autoload
 (defun +default/insert-file-path (arg)
   "Insert the file name (absolute path if prefix ARG).