Better document edit patch sets

Edit patch sets were, until now, not documented in the revision-info
entity definition.

Change-Id: Id875685a0510842295798619e12a4817054715ab
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index 7b51567..e453c7a 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -6834,7 +6834,7 @@
 |Field Name    ||Description
 |`kind`        ||The change kind. Valid values are `REWORK`, `TRIVIAL_REBASE`,
 `MERGE_FIRST_PARENT_UPDATE`, `NO_CODE_CHANGE`, and `NO_CHANGE`.
-|`_number`     ||The patch set number.
+|`_number`     ||The patch set number, or `edit` if the patch set is an edit.
 |`created`     ||
 The link:rest-api.html#timestamp[timestamp] of when the patch set was
 created.