Ensure spec is more explicit for clientId authorisation failures for …

…REST & Realtime

content/client-lib-development-guide/features.textile

@@ -90,7 +90,7 @@ h3(#rest-auth). Auth
 * @(RSA15)@ If Token Auth is selected and @clientId@ has been set in the @ClientOptions@ when the library was instanced:
 ** @(RSA15a)@ Any @clientId@ provided in @ClientOptions@ must match any non @null@ @clientId@ value in @TokenDetails@ or @connectionDetails@ of the @CONNECTED@ @ProtocolMessage@, where applicable
 ** @(RSA15b)@ If the @clientId@ from @TokenDetails@ or @connectionDetails@ contains only a wildcard string @'*'@, then the client is permitted to be either unauthenticated (effectively anonymous without a @clientId@) or authenticated providing a @clientId@ when communicating with Ably
-** @(RSA15c)@ Following an auth request which uses a @TokenDetails@ or @TokenRequest@ object that contains an incompatible @clientId@, the library should change the connection state to @FAILED@ and emit an error
+** @(RSA15c)@ Following an auth request which uses a @TokenDetails@ or @TokenRequest@ object that contains an incompatible @clientId@, the library should in the case of Realtime change the connection state to @FAILED@ and emit an error, and in the case of REST raise an exception
 * @(RSA5)@ TTL for new tokens is specified in milliseconds and defaults to the REST API default (1 hour)
 * @(RSA6)@ The @capability@, if not specified, defaults to allow all operations permitted for the key associated with the token
 * @(RSA7)@ @clientId@ and authenticated clients: