ForbidGroupingByNavigationPropertiesRule: base types (#51)

* ForbidGroupingByNavigationPropertiesRule: base types

* fix location

* revert

Mindbox.Analyzers/Rules/ForbidGroupingByNavigationPropertiesRule.cs

@@ -62,7 +62,7 @@ x.AttributeClass is not null
 			&& x.AttributeClass.ContainingNamespace.ToString() == "System.ComponentModel.DataAnnotations.Schema"
 			&& x.AttributeClass.Name == "TableAttribute");
 
-		return attributeData is not null;
+		return attributeData is not null || typeSymbol.BaseType is not null && HasTableAttribute(typeSymbol.BaseType);
 	}
 
 	private static bool TryGetGroupByProperty(