[[PR Description]]

Adds `script/deploy-docs`:
- If you don't already have it, it will clone the `zed-docs` repo into
`../zed-docs`
    - It will build the docs and output them in `../zed-docs`
    - Then it will open the docs.
- By default this "dry runs" (doesn't push) but you can pass `-p` to
push the changes.
    - If you add `-c` it will clean out the old docs before running.
    
If you run the script with `p` it will push up the changes, and vercel
will automatically deploy them.

Release Notes:

- N/A