keymap: Add subword navigation and selection to Sublime Text keymap (#30268)

For reference, this is what is set in Sublime Text's default-keymap
files for both MacOS and Linux:

```json
{ "keys": ["ctrl+left"], "command": "move", "args": {"by": "words", "forward": false} },
{ "keys": ["ctrl+right"], "command": "move", "args": {"by": "word_ends", "forward": true} },
{ "keys": ["ctrl+shift+left"], "command": "move", "args": {"by": "words", "forward": false, "extend": true} },
{ "keys": ["ctrl+shift+right"], "command": "move", "args": {"by": "word_ends", "forward": true, "extend": true} },
```

Release Notes:

- Add subword navigation and selection to Sublime keymap

Co-authored-by: Peter Tripp <peter@zed.dev>

assets/keymaps/linux/sublime_text.json

@@ -51,7 +51,11 @@
       "ctrl-k ctrl-l": "editor::ConvertToLowerCase",
       "shift-alt-m": "markdown::OpenPreviewToTheSide",
       "ctrl-backspace": "editor::DeleteToPreviousWordStart",
-      "ctrl-delete": "editor::DeleteToNextWordEnd"
+      "ctrl-delete": "editor::DeleteToNextWordEnd",
+      "ctrl-right": "editor::MoveToNextSubwordEnd",
+      "ctrl-left": "editor::MoveToPreviousSubwordStart",
+      "ctrl-shift-right": "editor::SelectToNextSubwordEnd",
+      "ctrl-shift-left": "editor::SelectToPreviousSubwordStart"
     }
   },
   {

assets/keymaps/macos/sublime_text.json

@@ -53,7 +53,11 @@
       "cmd-shift-j": "editor::JoinLines",
       "shift-alt-m": "markdown::OpenPreviewToTheSide",
       "ctrl-backspace": "editor::DeleteToPreviousWordStart",
-      "ctrl-delete": "editor::DeleteToNextWordEnd"
+      "ctrl-delete": "editor::DeleteToNextWordEnd",
+      "ctrl-right": "editor::MoveToNextSubwordEnd",
+      "ctrl-left": "editor::MoveToPreviousSubwordStart",
+      "ctrl-shift-right": "editor::SelectToNextSubwordEnd",
+      "ctrl-shift-left": "editor::SelectToPreviousSubwordStart"
     }
   },
   {