Add new hookshot list and remove command

chat/matrix/bridges.markdown

@@ -18,7 +18,7 @@ Base URL: `https://hookshot.mbot.ethz.ch/webhook/<hook>`
 1. Invite [hookshot](https://m.ethz.ch/#/@hookshot:mbot.ethz.ch) (`@hookshot:mbot.ethz.ch`) to your **unencrypted** room
 2. Give the bot permissions (Moderator)
 3. Send the message `!hookshot webhook <name>` (replace `<name>`)
-4. The bridge will send you an URL
+4. The bridge will send you an URL in a private admin room (DM)
 
 The bridge accepts POST or PUT requests. See [docs](https://matrix-org.github.io/matrix-hookshot/latest/setup/webhooks.html#webhook-handling) for details or the example below.
 
@@ -45,6 +45,12 @@ Example using `curl`:
 curl --header "Content-Type: application/json" --data '<payload>' "<url>"
 ```
 
+#### Remove webhooks
+
+In the room where webhooks were configured (not admin room):
+
+- List webhooks: `!hookshot webhook list`
+- Remove webhook: `!hookshot webhook remove <name>`
 
 ## Webhook API (Grafana, Slack)