Flash targets action (#2764)

Fixes #2271

## Checklist

- [x] 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)
- [/] I have not broken the cheatsheet

Author: AndreasArvidsson

src/spoken_forms.json

@@ -23,6 +23,7 @@
       "drink": "editNewLineBefore",
       "drop": "insertEmptyLineBefore",
       "extract": "extractVariable",
+      "flash": "flashTargets",
       "float": "insertEmptyLineAfter",
       "fold": "foldRegion",
       "follow split": "followLinkAside",