keymap_ui: Improve keybind display in menus (#34587)

Closes #ISSUE

Defines keybindings for `keymap_editor::EditBinding` and
`keymap_editor::CreateBinding`, making sure those actions are used in
tooltips.

Release Notes:

- N/A *or* Added/Fixed/Improved ...

---------

Co-authored-by: Finn <dev@bahn.sh>

assets/keymaps/default-linux.json

@@ -1118,7 +1118,9 @@
       "ctrl-f": "search::FocusSearch",
       "alt-find": "keymap_editor::ToggleKeystrokeSearch",
       "alt-ctrl-f": "keymap_editor::ToggleKeystrokeSearch",
-      "alt-c": "keymap_editor::ToggleConflictFilter"
+      "alt-c": "keymap_editor::ToggleConflictFilter",
+      "enter": "keymap_editor::EditBinding",
+      "alt-enter": "keymap_editor::CreateBinding"
     }
   },
   {

assets/keymaps/default-macos.json

@@ -1217,7 +1217,9 @@
     "use_key_equivalents": true,
     "bindings": {
       "cmd-alt-f": "keymap_editor::ToggleKeystrokeSearch",
-      "cmd-alt-c": "keymap_editor::ToggleConflictFilter"
+      "cmd-alt-c": "keymap_editor::ToggleConflictFilter",
+      "enter": "keymap_editor::EditBinding",
+      "alt-enter": "keymap_editor::CreateBinding"
     }
   },
   {