[docs] a broken link in docs

[Julien Palard]

Hi!

> https://docs.python.org/3.7/library/asyncio-protocol.html#transports
>
> Transport objects are always instantiated by an ref:asyncio event loop <asyncio-event-loop>.

Thanks for reporting Leo! It has been fixed on Feb 10 2019, are you sure you're still seeing it? What's the "Last updated on" date on the bottom right of the page?
Bests,
-- 
Julien Palard
https://mdk.fr