Change reaction events signature and name.

This changes the event signature to be (reaction, user) instead of
(message, reaction, user) since the reaction data class already has
the message being reacted to as a member.

The name was shortened from on_message_reaction_ to on_reaction_ since
the message prefix was deemed redundant.

discord/state.py

@@ -272,7 +272,7 @@ class ConnectionState:
             channel = self.get_channel(data['channel_id'])
             member = self._get_member(channel, data['user_id'])
 
-            self.dispatch('message_reaction_add', message, reaction, member)
+            self.dispatch('reaction_add', reaction, member)
 
     def parse_message_reaction_remove(self, data):
         message = self._get_message(data['message_id'])
@@ -291,7 +291,7 @@ class ConnectionState:
             channel = self.get_channel(data['channel_id'])
             member = self._get_member(channel, data['user_id'])
 
-            self.dispatch('message_reaction_remove', message, reaction, member)
+            self.dispatch('reaction_remove', reaction, member)
 
     def parse_presence_update(self, data):
         server = self._get_server(data.get('guild_id'))

docs/api.rst

@@ -207,23 +207,29 @@ to handle it, which defaults to print a traceback and ignore the exception.
     :param before: A :class:`Message` of the previous version of the message.
     :param after: A :class:`Message` of the current version of the message.
 
-.. function:: on_message_reaction_add(message, reaction, user)
+.. function:: on_reaction_add(reaction, user)
 
     Called when a message has a reaction added to it. Similar to on_message_edit,
     if the message is not found in the :attr:`Client.messages` cache, then this
     event will not be called.
 
-    :param message: A :class:`Message` that was reacted to.
+    .. note::
+
+        To get the message being reacted, access it via :attr:`Reaction.message`.
+
     :param reaction: A :class:`Reaction` showing the current state of the reaction.
     :param user: A :class:`User` or :class:`Member` of the user who added the reaction.
 
-.. function:: on_message_reaction_remove(message, reaction, user)
+.. function:: on_reaction_remove(reaction, user)
 
     Called when a message has a reaction removed from it. Similar to on_message_edit,
     if the message is not found in the :attr:`Client.messages` cache, then this event
     will not be called.
 
-    :param message: A :class:`Message` that was reacted to.
+    .. note::
+
+        To get the message being reacted, access it via :attr:`Reaction.message`.
+
     :param reaction: A :class:`Reaction` showing the current state of the reaction.
     :param user: A :class:`User` or :class:`Member` of the user who removed the reaction.
 
@@ -631,6 +637,12 @@ Message
 .. autoclass:: Message
     :members:
 
+Reaction
+~~~~~~~~~
+
+.. autoclass:: Reaction
+    :members:
+
 CallMessage
 ~~~~~~~~~~~~