Add note clarifying DELETE does not free up disk space (#1025)

Author: JPryce-Aklundh

modules/ROOT/pages/clauses/delete.adoc

@@ -9,7 +9,11 @@ The `DELETE` clause is used to delete nodes, relationships or paths.
 For removing properties and labels, see the xref::clauses/remove.adoc[REMOVE] clause.
 
 It is not possible to delete nodes with relationships connected to them without also deleting the relationships. 
-This can be done by either explicitly deleting specific relationships, or by using the `DETACH DELETE` clause. 
+This can be done by either explicitly deleting specific relationships, or by using the `DETACH DELETE` clause.
+
+[NOTE]
+While the `DELETE` clause renders the deleted objects no longer accessible, the space occupied by the deleted nodes and relationships remain on the disk and is reserved for future transactions creating data.
+For information about how to clear and reuse the space occupied by deleted objects, see link:{neo4j-docs-base-uri}/operations-manual/{page-version}/performance/space-reuse/[Operations Manual -> Space reuse].
 
 == Example graph