plugin XEP-0424: rename bridge method:

``messRetract`` is renamed to ``messageRetract`` for consistency with other message bridge
methods.

sat/plugins/plugin_xep_0424.py

@@ -76,7 +76,7 @@ class XEP_0424(object):
         host.registerNamespace("message-retract", NS_MESSAGE_RETRACT)
         host.trigger.add("messageReceived", self._messageReceivedTrigger, 100)
         host.bridge.addMethod(
-            "messRetract",
+            "messageRetract",
             ".plugin",
             in_sign="ss",
             out_sign="",

sat_frontends/jp/cmd_message.py

@@ -200,7 +200,7 @@ class Retract(base.CommandBase):
 
     async def start(self):
         try:
-            await self.host.bridge.messRetract(
+            await self.host.bridge.messageRetract(
                 self.args.message_id,
                 self.profile
             )