Add short message: &incompatible (#601)

masterlist.yaml

@@ -228,6 +228,10 @@ prelude:
       detail: 'It is strongly recommended not to use mods that contain **deleted navmeshes** as they''re known to cause crashes. **Deleted navmeshes** must be corrected manually (a complex process that should be done by the mod author). More information on **deleted navmeshes** is provided [here](https://www.creationkit.com/index.php?title=Fixing_Navmesh_Deletion_Tutorial).'
 
   # Global Anchors
+    - &incompatible
+      type: error
+      content: '{0} is incompatible with {1}, but both are present.'
+
     - &latestLOOTThread
       type: say
       content: '[Latest LOOT thread]({0}).'