[clang-tools-extra] [llvm] [clang-tools-extra][docs] Use Furo theme to match clang (PR #222196)

[Baranov Victor via cfe-commits]

https://github.com/vbvictor requested changes to this pull request.

I have 21x9 monitor (LG 38WR85QC-W) and some tables seem to render incorrectly:

Before:

<img width="3681" height="1466" alt="Image" src="https://github.com/user-attachments/assets/40aa7d85-b3ab-420d-9516-4dc4984052bb" />

After:

<img width="3681" height="1466" alt="Image" src="https://github.com/user-attachments/assets/1c0e7886-1673-4d0d-af44-d5357290cfb1" />

See how "Redirect" field is not fully available and "Offers fixes" basically not existent on new version.

If I zoom in/out it doesnt make any difference:

<img width="2229" height="1444" alt="Image" src="https://github.com/user-attachments/assets/e739154f-9fa4-4338-8e29-4aa56d04728f" />

Not sure if this happens on other monitors, but for 21x9 its a downgrade and I hope we won't commit it like this.

https://github.com/llvm/llvm-project/pull/222196