Updating the docs to match latest skywater-pdk.

Taken from https://github.com/google/skywater-pdk
```
commit b5ff6174d9aa921f670f12a2893969fe4a516f6c (HEAD -> main, upstream/main)
Merge: 5e159bd 73e9c84
Author: Tim Ansell <me@mith.ro>
Date:   Tue Nov 2 13:28:11 2021 -0700

    Merge pull request #341 from mithro/sphinx-theme-fix

    Update the sphinx theme
```

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>
17 files changed