Clarify provider naming

Author: turt2live

content/client-server-api/modules/sso_login.md

@@ -40,10 +40,8 @@ administrator to configure where the CAS server is and the REST
 endpoints which consume the ticket.
 
 Homeservers may optionally expose multiple possible SSO options for
-the user to pursue, typically in the form of several "login with $service"
-buttons. These services, or "identity providers" (IdPs), are typically
-OpenID Connect, though the exact protocol used is not a concern for this
-specification.
+the user to pursue, typically in the form of several "login with $provider"
+buttons. These are known as "identity providers" (IdPs).
 
 #### Client login via SSO