[[PR Description]]

Started building out some early components in the storybook using a
modified version of the classic Atomic Design model @mikayla-maki and I
are exploring.

<img width="1134" alt="atomic_design"
src="https://github.com/zed-industries/zed/assets/1714999/9093a8b5-a71d-41d4-bae2-f7562494c5f3">

This PR adds a few things:

- `tab`, `tab_bar` and `icon_button` components
- Dynamic documentation for the proc macro generated methods like `w_8`,
`px_2`, etc.
- Continues to build out the Zed workspace demo

Release Notes:

- N/A