Fix a bug I introduced in GH-9864 by which coroutines are treated as synonymous of function coroutines.

Also, fix the same mistake (coroutines == function coroutines) already present in other parts of the reference.

I'm very sorry for the hassle.
(cherry picked from commit 95f68b10)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>