In #25005 we added regex syntax highlighting to search; but the existing
regex grammar highlighted every character as a string which was hard to
read.

This flips so that characters are not highlighted, and brackets, etc.
are.
<img width="346" alt="Screenshot 2025-03-03 at 14 39 35"
src="https://github.com/user-attachments/assets/f7d3ae9c-fb5c-45eb-a5e9-41a330fbe940"
/>


Release Notes:

- Fixed regex search box being overly green