synapse/changelog.d/14179.feature

Improve the validation of the following PUT endpoints: [`/directory/room/{roomAlias}`](https://spec.matrix.org/v1.4/client-server-api/#put_matrixclientv3directoryroomroomalias), [`/directory/list/room/{roomId}`](https://spec.matrix.org/v1.4/client-server-api/#put_matrixclientv3directorylistroomroomid) and [`/directory/list/appservice/{networkId}/{roomId}`](https://spec.matrix.org/v1.4/application-service-api/#put_matrixclientv3directorylistappservicenetworkidroomid).