[DOCS] Remove non-valid link to mapping migration document

docs/reference/migration/migrate_6_0.asciidoc

@@ -24,15 +24,12 @@ way to reindex old indices is to use the `reindex` API.
 [float]
 === Also see:
 
-* <<breaking_60_mapping_changes>>
 * <<breaking_60_rest_changes>>
 * <<breaking_60_search_changes>>
 * <<breaking_60_docs_changes>>
 * <<breaking_60_cluster_changes>>
 * <<breaking_60_plugins_changes>>
 
-include::migrate_6_0/mapping.asciidoc[]
-
 include::migrate_6_0/rest.asciidoc[]
 
 include::migrate_6_0/search.asciidoc[]