vim: Sentence motion (#17425)

Closes #12161

Release Notes:

- vim: Added `(` and `)` for sentence motion

assets/keymaps/vim.json

@@ -29,6 +29,8 @@
       "shift-g": "vim::EndOfDocument",
       "{": "vim::StartOfParagraph",
       "}": "vim::EndOfParagraph",
+      "(": "vim::SentenceBackward",
+      ")": "vim::SentenceForward",
       "|": "vim::GoToColumn",
       // Word motions
       "w": "vim::NextWordStart",