Update some external links on the docs

[pmhaddad]

The issue

I believe during the conversion from .rst to .md a minor typo was introduced on the link for python-dotenv repo on pipenv docs

The fix

Remove the extra >

ps.: Since this typo was observed, I took the liberty to grep the repo and see if there were similar cases. I found three more that seemed relevant. Note that in the TOML case, the Spec header was moved from the READ.md into their docs

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.