Fix broken contributing link on PyPI

[staticdev]

• When you remove github-only RST session and put full paths to RTD it simply works everywhere.
  I tried in my own repo, you can check out: https://pypi.org/project/git-portfolio/

Closes cjolowicz/cookiecutter-hypermodern-python#1091

[cjolowicz]

Thanks for catching this!

The problem with your approach is that it will silently switch versions on Read the Docs.

[cjolowicz]

Better keep the github-only marker and use the full GitHub URL (main branch) instead of a relative link.

pros:

• RTD versioning isn't broken by silently switching to latest
• GitHub readers stay on GitHub

cons:

• GitHub readers might switch branch when clicking the link

I think the pros outweigh the cons.

Like you say, PyPI readers will get the GitHub version which is less polished. But it's the Contributor Guide, contributors want to go to GitHub anyway 😉

[staticdev]

@cjolowicz oh I see the problem. Ok, I fix that later today.

[cjolowicz]

Thank you!