Update document of 'Move Change' REST endpoint

This change updates the 'Move Change' doc to notice users
the difference between this endpoint and the cherry-pick
endpoint.

Change-Id: Ibf29e4493d1d1c962cc7e45c9526f9317957efc5

Documentation/rest-api-changes.txt

diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index b8c6025..557fb3c 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -1312,6 +1312,9 @@
   }
 ----
 
+Note that this endpoint will not update the change's parents, which is
+different from the link:#cherry-pick[cherry-pick] endpoint.
+
 If the change cannot be moved because the change state doesn't
 allow moving the change, the response is "`409 Conflict`" and
 the error message is contained in the response body.