Don't love how this turned out, it seems uniform list doesn't tie the
widths of its items together, so there needs to be a set size to fill in
order to put the documentation detail on the right side. That means it
won't be able to shrink for completion lists which don't need the full
width. Zed1 has this same limitation but it would be nice to do it nicer
now

Before
![CleanShot 2024-01-02 at 16 04
04](https://github.com/zed-industries/zed/assets/30666851/6c154465-83cd-41c3-a16a-5f2ff5041bc1)

After
![CleanShot 2024-01-02 at 16 05
29](https://github.com/zed-industries/zed/assets/30666851/4f641040-a06a-4474-a2c7-bd3c89ae049e)

Release Notes:

- N/A