Describe relation in tooltip in add membership list

modules/ui/raw_membership_editor.js

@@ -1,5 +1,6 @@
 import _extend from 'lodash-es/extend';
 import _filter from 'lodash-es/filter';
+import _forEach from 'lodash-es/forEach';
 import _groupBy from 'lodash-es/groupBy';
 
 import {
@@ -115,6 +116,10 @@ export function uiRawMembershipEditor(context) {
             });
         });
 
+        _forEach(result, function(obj) {
+            obj.title = obj.value;
+        });
+
         result.unshift(newRelation);
         return result;
     }