Document permalinkPrefix setting
Document permalinkPrefix setting

There's no sample config changes because we don't want to encourage people using this setting. It is for very limited scenarios only: unfederated servers.
vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/vector-web,vector-im/riot-web,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/riot-web