Fix grammar in registration text
Fix grammar in registration text

I assume some script needs to be run to generate the other string files, but if you want to just do that yourselves and take the text in this PR I'm totally fine with that.

vector-im/riot-ios,vector-im/riot-ios,vector-im/riot-ios,vector-im/vector-ios,vector-im/riot-ios,vector-im/vector-ios,vector-im/riot-ios,vector-im/vector-ios,vector-im/riot-ios