This PR adds a new `ToggleButton` component:

<img width="738" alt="Screenshot 2023-12-20 at 6 50 13 PM"
src="https://github.com/zed-industries/zed/assets/1486634/9c5fb45b-0b55-4008-9336-b651a26a99ad">

We're using `ToggleButton`s for the search mode selection in the buffer
search:

<img width="842" alt="Screenshot 2023-12-20 at 6 47 57 PM"
src="https://github.com/zed-industries/zed/assets/1486634/178a278f-172c-4c67-8572-83d59de2ed14">

Release Notes:

- N/A