[client_channel] Better trace message (#33121)

(this helped diagnose what was going on in another bug)

src/core/ext/filters/client_channel/client_channel.cc

@@ -1492,7 +1492,8 @@ void ClientChannel::UpdateServiceConfigInDataPlaneLocked() {
 
 void ClientChannel::CreateResolverLocked() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_trace)) {
-    gpr_log(GPR_INFO, "chand=%p: starting name resolution", this);
+    gpr_log(GPR_INFO, "chand=%p: starting name resolution for %s", this,
+            uri_to_resolve_.c_str());
   }
   resolver_ = CoreConfiguration::Get().resolver_registry().CreateResolver(
       uri_to_resolve_.c_str(), channel_args_, interested_parties_,