properties: PropertyImpl#getParent overrides and delegates call to getParentByStub()

plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/psi/impl/PropertyImpl.java

@@ -459,4 +459,9 @@ public class PropertyImpl extends PropertiesStubElementImpl<PropertyStub> implem
     LOG.assertTrue(newDelimiter != null);
     getNode().replaceChild(oldDelimiter, newDelimiter);
   }
+
+  @Override
+  public PsiElement getParent() {
+    return getParentByStub();
+  }
 }