Update webhook api docs

chat/matrix/bridges.markdown

@@ -67,7 +67,7 @@ Base URL: `https://webhooks.mbot.ethz.ch/webhook/grafana/<hook>`
 
 In [Grafana](https://grafana.phys.ethz.ch) ([Docs](https://readme.phys.ethz.ch/documentation/grafana/#sending-alerts-to-matrix)):
 
-1. Create a contact point for the room: **Alerting** > **Contact points** > **Add contact point**
+1. Create a contact point: **Alerting** > **Contact points** > **Add contact point**
 2. Add a **Name** and select **Integration**: `Webhook`
 3. Paste the url into the **URL** field
 
@@ -81,7 +81,7 @@ for details.
 
 Base URL: `https://webhooks.mbot.ethz.ch/webhook/slack/<hook>`
 
-1. Create a contact point for the room: **Alerting** > **Contact points** > **Add contact point**
+1. Create a contact point: **Alerting** > **Contact points** > **Add contact point**
 2. Select **Integration**: `Slack`
 3. Paste the url into the **Webhook URL** field
 4. Optional: Set **Optional Slack settings** > **Username** to `Grafana`