[DOCS] Removes notable breaking changes section

Author: lcawl

docs/reference/migration/migrate_7_0.asciidoc

@@ -9,7 +9,6 @@ your application to Elasticsearch 7.0.
 
 See also <<release-highlights>> and <<es-release-notes>>.
 
-* <<breaking_70_notable>>
 * <<breaking_70_aggregations_changes>>
 * <<breaking_70_cluster_changes>>
 * <<breaking_70_discovery_changes>>
@@ -31,10 +30,8 @@ See also <<release-highlights>> and <<es-release-notes>>.
 * <<breaking_70_node_changes>>
 * <<breaking_70_java_time_changes>>
 
-[float]
-[[breaking_70_notable]]
-=== Notable changes
-// NOTE: The content in this section is also used in the Installation and Upgrade Guide.
+//NOTE: The notable-breaking-changes tagged regions are re-used in the
+//Installation and Upgrade Guide
 
 //tag::notable-breaking-changes[]
 [float]