issue2550966: fix suboptimal links in docs. I think I got the majority of them. Some links still don't resolve because they are gone and there is no replacement afaict. Also the check is picking up example links like: https://.../rest and http://localhost:8017/... which should not be checked but are.

[run]

# ignore the dist utils. They are not part of the code base
# we are going to test. They are used by maintainers only.
omit = roundup/dist/*