It was wrong for ruma-federation-api and useless for all others since crates.io will link to docs.rs automatically if no link is given.
ruma
Types and traits for working with the Matrix protocol.
This crate re-exports things from all of the other ruma crates so you don't have to manually keep all the versions in sync.
Which crates are re-exported can be configured through cargo features. Depending on which parts of Matrix are relevant to you, activate the following features:
client-api
for the client-server APIfederation-api
for the server-server (federation) APIappservice-api
for the application service API