Add shard related connection and resume events.

These include:
* on_shard_resumed
* on_shard_connect
* on_shard_disconnect

docs/api.rst

@@ -117,6 +117,16 @@ to handle it, which defaults to print a traceback and ignoring the exception.
 
     The warnings on :func:`on_ready` also apply.
 
+.. function:: on_shard_connect(shard_id)
+
+    Similar to :func:`on_connect` except used by :class:`AutoShardedClient`
+    to denote when a particular shard ID has connected to Discord.
+
+    .. versionadded:: 1.4
+
+    :param shard_id: The shard ID that has connected.
+    :type shard_id: :class:`int`
+
 .. function:: on_disconnect()
 
     Called when the client has disconnected from Discord. This could happen either through
@@ -125,6 +135,16 @@ to handle it, which defaults to print a traceback and ignoring the exception.
 
     This function can be called many times.
 
+.. function:: on_shard_disconnect(shard_id)
+
+    Similar to :func:`on_disconnect` except used by :class:`AutoShardedClient`
+    to denote when a particular shard ID has disconnected from Discord.
+
+    .. versionadded:: 1.4
+
+    :param shard_id: The shard ID that has disconnected.
+    :type shard_id: :class:`int`
+
 .. function:: on_ready()
 
     Called when the client is done preparing the data received from Discord. Usually after login is successful
@@ -149,6 +169,16 @@ to handle it, which defaults to print a traceback and ignoring the exception.
 
     Called when the client has resumed a session.
 
+.. function:: on_shard_resumed(shard_id)
+
+    Similar to :func:`on_resumed` except used by :class:`AutoShardedClient`
+    to denote when a particular shard ID has resumed a session.
+
+    .. versionadded:: 1.4
+
+    :param shard_id: The shard ID that has resumed.
+    :type shard_id: :class:`int`
+
 .. function:: on_error(event, \*args, \*\*kwargs)
 
     Usually when an event raises an uncaught exception, a traceback is