Add new /forge entity list command for displaying a list of all entities in world.

As well as tracking down chunks with large amounts of entities.

src/main/java/net/minecraftforge/registries/GameData.java

@@ -572,7 +572,7 @@ public class GameData
                 RegistryEvent.MissingMappings<?> event = reg.getMissingEvent(name, m.getValue());
                 MinecraftForge.EVENT_BUS.post(event);
 
-                List<MissingMappings.Mapping<?>> lst = event.getAllMappings().stream().filter(e -> e.getAction() == MissingMappings.Action.DEFAULT).collect(Collectors.toList());
+                List<MissingMappings.Mapping<?>> lst = event.getAllMappings().stream().filter(e -> e.getAction() == MissingMappings.Action.DEFAULT).sorted((a, b) -> a.toString().compareTo(b.toString())).collect(Collectors.toList());
                 if (!lst.isEmpty())
                 {
                     FMLLog.log.error("Unidentified mapping from registry {}", name);