[Docs] Update link in removal_of_types.asciidoc
Fix link to [parent-child relationship].
@@ -41,7 +41,7 @@ field, so documents of different types with the same `_id` could exist in a
single index.
Mapping types were also used to establish a
-/guide/en/elasticsearch/reference/5.4/mapping-parent-field.html[parent-child relationship]
+<<mapping-parent-field,parent-child relationship>>
between documents, so documents of type `question` could be parents to
documents of type `answer`.
