add listener api changes to docs notebook

Author: bollwyvl

docs/Extending.ipynb

@@ -120,9 +120,9 @@
     "def load_jupyter_server_extension(nbapp):\n",
     "\n",
     "    @lsp_message_listener(\"all\")\n",
-    "    async def my_listener(scope, message, languages, manager):\n",
-    "        print(\"received a {} {} message about {}\".format(\n",
-    "          scope, message[\"method\"], languages\n",
+    "    async def my_listener(scope, message, language_server, manager):\n",
+    "        print(\"received a {} {} message from {}\".format(\n",
+    "          scope, message[\"method\"], language_server\n",
     "        ))\n",
     "```\n",
     "\n",
@@ -138,7 +138,7 @@
     "Fine-grained controls are available as part of the Python API. Pass these as\n",
     "named arguments to `lsp_message_listener`.\n",
     "\n",
-    "- `languages`: a regular expression of languages\n",
+    "- `language_server`: a regular expression of language servers\n",
     "- `method`: a regular expression of LSP JSON-RPC method names"
    ]
   }