pane: Add keybinding to "Close Left" and "Close Right" actions (#22402)

Was super missing these as I use these actions all the time 😄 

<img width="680" alt="Screenshot 2024-12-24 at 3 18 04 PM"
src="https://github.com/user-attachments/assets/5dbf9ebd-afc5-438c-aad7-c17ca59d9f9b"
/>

Release Notes:

- Add keybinding to "Close Left" and "Close Right" actions

assets/keymaps/default-linux.json

@@ -260,6 +260,8 @@
       "ctrl-f4": "pane::CloseActiveItem",
       "alt-ctrl-t": ["pane::CloseInactiveItems", { "close_pinned": false }],
       "alt-ctrl-shift-w": "workspace::CloseInactiveTabsAndPanes",
+      "ctrl-k e": ["pane::CloseItemsToTheLeft", { "close_pinned": false }],
+      "ctrl-k t": ["pane::CloseItemsToTheRight", { "close_pinned": false }],
       "ctrl-k u": ["pane::CloseCleanItems", { "close_pinned": false }],
       "ctrl-k w": ["pane::CloseAllItems", { "close_pinned": false }],
       "ctrl-shift-f": "project_search::ToggleFocus",