Fix missing IMC message query.

src/main/java/net/minecraftforge/fml/common/event/FMLInterModComms.java

@@ -221,6 +221,15 @@ public class FMLInterModComms {
             return NBTTagCompound.class.isAssignableFrom(getMessageType());
         }
 
+        /**
+         * Is this an {@link ResourceLocation} type message
+         * @return if this is an NBT type message
+         */
+        public boolean isResourceLocationMessage()
+        {
+            return ResourceLocation.class.isAssignableFrom(getMessageType());
+        }
+
         /**
          * Is this a {@link Function} type message
          * @return if this is a function type message