Use google style doc strings.

pycharm supports them so there is no need to use the other format.

Might as well convert the existing strings to reduce the risk of
people accidentally cargo culting the wrong doc string format.

synapse/storage/event_push_actions.py

@@ -26,8 +26,9 @@ logger = logging.getLogger(__name__)
 class EventPushActionsStore(SQLBaseStore):
     def _set_push_actions_for_event_and_users_txn(self, txn, event, tuples):
         """
-        :param event: the event set actions for
-        :param tuples: list of tuples of (user_id, actions)
+        Args:
+            event: the event set actions for
+            tuples: list of tuples of (user_id, actions)
         """
         values = []
         for uid, actions in tuples:

synapse/storage/registration.py

@@ -458,12 +458,15 @@ class RegistrationStore(SQLBaseStore):
         """
         Gets the 3pid's guest access token if exists, else saves access_token.
 
-        :param medium (str): Medium of the 3pid. Must be "email".
-        :param address (str): 3pid address.
-        :param access_token (str): The access token to persist if none is
-            already persisted.
-        :param inviter_user_id (str): User ID of the inviter.
-        :return (deferred str): Whichever access token is persisted at the end
+        Args:
+            medium (str): Medium of the 3pid. Must be "email".
+            address (str): 3pid address.
+            access_token (str): The access token to persist if none is
+                already persisted.
+            inviter_user_id (str): User ID of the inviter.
+
+        Returns:
+            deferred str: Whichever access token is persisted at the end
             of this function call.
         """
         def insert(txn):

synapse/storage/state.py

@@ -249,11 +249,14 @@ class StateStore(SQLBaseStore):
         """
         Get the state dict corresponding to a particular event
 
-        :param str event_id: event whose state should be returned
-        :param list[(str, str)]|None types: List of (type, state_key) tuples
-            which are used to filter the state fetched. May be None, which
-            matches any key
-        :return: a deferred dict from (type, state_key) -> state_event
+        Args:
+            event_id(str): event whose state should be returned
+            types(list[(str, str)]|None): List of (type, state_key) tuples
+                which are used to filter the state fetched. May be None, which
+                matches any key
+
+        Returns:
+            A deferred dict from (type, state_key) -> state_event
         """
         state_map = yield self.get_state_for_events([event_id], types)
         defer.returnValue(state_map[event_id])