test multiple xmlfiles in error

src/rougail/annotator.py

@@ -1064,7 +1064,8 @@ class ConstraintAnnotator:
             fill = fills[idx]
             # test if it's redefined calculation
             if fill.target in targets and not fill.redefine:
-                raise DictConsistencyError(_(f"A fill already exists for the target: {fill.target}"))
+                xmlfiles = self.objectspace.display_xmlfiles(fill.xmlfiles)
+                raise DictConsistencyError(_(f'A fill already exists for the target of "{fill.target}" created in {xmlfiles}'))
             targets.append(fill.target)
             #
             if fill.name not in self.functions:

src/rougail/objspace.py

@@ -323,8 +323,7 @@ class CreoleObjSpace:
                          ) -> str:
         if len(xmlfiles) == 1:
             return '"' + xmlfiles[0] + '"'
-        else:
-            return '"' + '", "'.join(xmlfiles[:-1]) + '"' + ' and ' + '"' + xmlfiles[-1] + '"'
+        return '"' + '", "'.join(xmlfiles[:-1]) + '"' + ' and ' + '"' + xmlfiles[-1] + '"'
 
     def create_tree_structure(self,
                               space,