rest.rst: Add patch-state-change event reference to documentation

Signed-off-by: Jose Lamego <jose.a.lamego@linux.intel.com>

docs/rest.rst

@@ -194,6 +194,7 @@ Events
                     "name": "series-new-revision",
                     "event_time": "2015-10-20T19:49:49.494183",
                     "series": 23,
+                    "patch": null,
                     "user": null,
                     "parameters": {
                         "revision": 2
@@ -202,12 +203,14 @@ Events
                 {
                 },
                 {
-                    "name": "series-new-revision",
-                    "event_time": "2015-10-20T19:49:43.895382",
-                    "series": 22,
-                    "user": null,
+                    "name": "patch-state-change",
+                    "event_time": "2016-02-18T09:30:33.853206",
+                    "series": 285,
+                    "patch": 685
+                    "user": 1,
                     "parameters": {
-                        "revision": 1
+                        "new_state": "Under Review",
+                        "previous_state": "New"
                     }
                 }
             ]
@@ -220,7 +223,7 @@ Events
                   retrieve events that haven't been seen yet.
 
 Each event type has some ``parameters`` specific to that event. At the moment,
-only one event is possible:
+two events are possible:
 
 - **series-new-revision**: This event corresponds to patchwork receiving a new
   revision of a series, should it be the initial submission or subsequent
@@ -234,6 +237,9 @@ only one event is possible:
   ``series`` and ``revision`` can be used to retrieve the corresponding
   patches.
 
+- **patch-state-change**: This event corresponds to patchwork receiving a
+  patch state change, either automatic or manually performed by an authorized
+  user, who will be identified by its patchwork-user id.
 
 Series
 ~~~~~~
@@ -590,6 +596,8 @@ API Revisions
   `submitted_before` and `updated_before` query parameters to the list of
   series entry points.
 
+- Add the patch-state-change event.
+
 **Revision 2**
 
 - Add mbox entry points for both patches and series: