Publishing doc fixes

Further cleanups to the publishing doc to avoid sharp edges and fix a formatting error.

Testing Done:
Eyeballed:
./build-support/bin/publish_docs.sh -o

Reviewed at https://rbcommons.com/s/twitter/r/1136/
Sync of https://github.com/pantsbuild/pants/commit/d441fc2b758e8a54a93c60a22f5d9ddce25459bf