Fix Socket Mode document

Author: seratch

docs/_basic/socket_mode.md

@@ -9,6 +9,16 @@ order: 16
 With the introduction of [Socket Mode](https://api.slack.com/apis/connections/socket), Bolt for Python introduced support in version `1.2.0`. With Socket Mode, instead of creating a server with endpoints that Slack sends payloads too, the app will instead connect to Slack via a WebSocket connection and receive data from Slack over the socket connection. Make sure to enable Socket Mode in your app configuration settings. 
 
 To use the Socket Mode, add `SLACK_APP_TOKEN` as an environment variable. You can get your App Token in your app configuration settings under the **Basic Information** section. 
+
+While we recommend using [the built-in Socket Mode adapter](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/builtin), there are a few other 3rd party library based implementations. Here is the list of available adapters.
+
+|PyPI Project|Bolt Adapter|
+|-|-|
+|[slack_sdk](https://pypi.org/project/slack-sdk/)|[slack_bolt.adapter.socket_mode](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/builtin)|
+|[websocket_client](https://pypi.org/project/websocket_client/)|[slack_bolt.adapter.socket_mode.websocket_client](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/websocket_client)|
+|[aiohttp](https://pypi.org/project/aiohttp/) (asyncio-based)|[slack_bolt.adapter.socket_mode.aiohttp](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/aiohttp)|
+|[websockets](https://pypi.org/project/websockets/) (asyncio-based)|[slack_bolt.adapter.socket_mode.websockets](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/websockets)|
+
 </div>
 
 ```python
@@ -19,30 +29,35 @@ from slack_bolt.adapter.socket_mode import SocketModeHandler
 # Install the Slack app and get xoxb- token in advance
 app = App(token=os.environ["SLACK_BOT_TOKEN"])
 
+# Add middleware / listeners here
+
 if __name__ == "__main__":
     # export SLACK_APP_TOKEN=xapp-***
     # export SLACK_BOT_TOKEN=xoxb-***
-    SocketModeHandler(app, os.environ["SLACK_APP_TOKEN"]).start()
+    handler = SocketModeHandler(app, os.environ["SLACK_APP_TOKEN"])
+    handler.start()
 ```
 
-While we recommend using [the built-in Socket Mode adapter](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/builtin), there are a few other 3rd party library based implementations. Here is the list of available adapters. 
-
-|PyPI Project|Bolt Adapter|
-|-|-|
-|[slack_sdk](https://pypi.org/project/slack-sdk/)|[slack_bolt.adapter.socket_mode](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/builtin)|
-|[websocket_client](https://pypi.org/project/websocket_client/)|[slack_bolt.adapter.socket_mode.websocket_client](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/websocket_client)|
-|[aiohttp](https://pypi.org/project/aiohttp/) (asyncio-based)|[slack_bolt.adapter.socket_mode.aiohttp](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/aiohttp)|
-|[websockets](https://pypi.org/project/websockets/) (asyncio-based)|[slack_bolt.adapter.socket_mode.websockets](https://github.com/slackapi/bolt-python/tree/main/slack_bolt/adapter/socket_mode/websockets)|
+<details class="secondary-wrapper">
+<summary markdown="0">
+<h4 class="secondary-header">Using Async</h4>
+</summary>
 
+<div class="secondary-content" markdown="0">
 To use the asyncio-based adapters such as aiohttp, your app needs to be compatible with asyncio's async/await programming model. `AsyncSocketModeHandler` is available for running `AsyncApp` and its async middleware and listeners. 
 
+To learn how to use `AsyncApp`, checkout the [Using Async](https://slack.dev/bolt-python/concepts#async) document and relevant [examples](https://github.com/slackapi/bolt-python/tree/main/examples).
+</div>
+
 ```python
 from slack_bolt.app.async_app import AsyncApp
 # The default is the aiohttp based implementation
 from slack_bolt.adapter.socket_mode.async_handler import AsyncSocketModeHandler
 
 app = AsyncApp(token=os.environ["SLACK_BOT_TOKEN"])
 
+# Add middleware / listeners here
+
 async def main():
     handler = AsyncSocketModeHandler(app, os.environ["SLACK_APP_TOKEN"])
     await handler.start_async()
@@ -52,4 +67,4 @@ if __name__ == "__main__":
     asyncio.run(main())
 ```
 
-To learn how to use `AsyncApp`, checkout the [Using Async](https://slack.dev/bolt-python/concepts#async) document and relevant [examples](https://github.com/slackapi/bolt-python/tree/main/examples).
+</details>