Change the answer method name

Author: martinRenou

ipywidgets/widgets/widget.py

@@ -351,7 +351,7 @@ def handle_control_comm_msg(cls, msg):
                 }
             full_state, buffer_paths, buffers = _remove_buffers(full_state)
             cls._control_comm.send(dict(
-                method='states',
+                method='update_states',
                 states=full_state,
                 buffer_paths=buffer_paths
             ), buffers=buffers)

packages/schema/messages.md

@@ -363,13 +363,13 @@ When a frontend wants to request the full state of a all widgets, the frontend s
 }
 ```
 
-The kernel side of the widget should immediately send an `states` message with all widgets states:
+The kernel side of the widget should immediately send an `update_states` message with all widgets states:
 
 ```
 {
   'comm_id' : 'u-u-i-d',
   'data' : {
-    'method': 'states',
+    'method': 'update_states',
     'states': {
       <widget1 u-u-i-d>: <widget1 state>,
       <widget2 u-u-i-d>: <widget2 state>,