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>