Fix a reST markup issue

[brettcannon]

No description provided.

[vstinner]

Merged, thanks!

[Mariatta]

🤔 When I go to http://asyncio.readthedocs.io/en/latest/why_asyncio.html, the url is still not properly linked. Screenshot:

[vstinner]

On https://readthedocs.org/projects/asyncio/builds/ I see that the last build was done two months ago :-( It seems like the hook from GitHub to ReadTheDocs has issues. On https://twitter.com/githubstatus I regulary see issues with webhooks, can it be related?

Anyway, at least for this commit, I forced a new build.

If someone wants to investigate, give me your ReadTheDocs login. Currently, @brettcannon and me are maintainers of https://readthedocs.org/dashboard/asyncio/users/

I can also give you access to the GitHub project if you want. Sadly, the only configuration is the webhook configured in GitHub and it's still there...

[brettcannon]

Maybe try removing and adding the Read the Docs hook again?