truncate url responses

yobot/plugins/url.py

@@ -111,6 +111,8 @@ class Plugin(IPlugin):
             for link in get_links(self.linkify, msg):
                 try:
                     res = await self.metadata(link)
+                    if len(res) > 400:
+                        res = res[:400] + "..."
                 except Exception as e:
                     traceback.print_exc()
                     print("error", e)