service/set: Convert GetLanguageCode over to using PushEnum()

This code was around prior to the introduction of PushEnum, so convert
it over so we don't need to cast here.

src/core/hle/service/set/set.cpp

@@ -112,7 +112,7 @@ void SET::GetLanguageCode(Kernel::HLERequestContext& ctx) {
 
     IPC::ResponseBuilder rb{ctx, 4};
     rb.Push(RESULT_SUCCESS);
-    rb.Push(static_cast<u64>(available_language_codes[Settings::values.language_index]));
+    rb.PushEnum(available_language_codes[Settings::values.language_index]);
 }
 
 SET::SET() : ServiceFramework("set") {