✨ feat(smart-splits)!: add resize-mode keymap

Adds a keymap to initialize resize mode for splits.

BREAKING CHANGE: This requires an accompanying change in the kitty
config (see commit: rootiest-kitty- #9998018)

lua/config/keymaps.lua

@@ -97,6 +97,13 @@ local resize_splits = {
     end,
     "Resize split right",
   },
+  {
+    "<A-r>",
+    function()
+      smartsplits.start_resize_mode()
+    end,
+    "Resize split to previous size",
+  },
 }
 
 for _, map in ipairs(resize_splits) do