Add .DS_Store to .gitignore for cursorless-talon (#2653)

When this is synced to
[`cursorless-talon`](https://github.com/cursorless-dev/cursorless-talon)
the `.gitignore` in the monorepo doesn't apply so copy the `.DS_Store`
ignore for those on macOS to prevent spurious `untracked content`
messages in `git`.

I don't think the checklist below applies in this case.

## Checklist

- [ ] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [ ] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [x] I have not broken the cheatsheet

Author: bentitmus

.gitignore

@@ -1,3 +1,4 @@
 *.flac
 data/
 .vscode/settings.json
+.DS_Store