webhooks/github_webhook: Update text to conform to doc style guide.

zerver/webhooks/github_webhook/doc.md

@@ -4,30 +4,18 @@ see [here](./github).
 
 1. {!create-stream.md!}
 
-2. {!create-bot-construct-url-indented.md!}
+1. {!create-bot-construct-url-indented.md!}
 
-3. {!git-webhook-url-with-branches-indented.md!}
+   {!git-webhook-url-with-branches-indented.md!}
 
-4. Next, go to your repository page and click **Settings**:
-   ![](/static/images/integrations/github_webhook/001.png)
+1. Go to your repository on GitHub and click on the **Settings** tab.
+   Select **Webhooks**. Click on **Add webhook**. GitHub may prompt
+   you for your password.
 
-5. From there, select **Webhooks**:
-
-    ![](/static/images/integrations/github_webhook/002.png)
-
-6. Click **Add webhook**.
-
-    ![](/static/images/integrations/github_webhook/003.png)
-
-7. Authorize yourself and configure your webhook.
-
-8. In the **Payload URL** field, enter the URL constructed above.
-
-9. Then, set **Content type** to `application/json`.
-
-10. Next, select the actions that you want to result in a Zulip
-    notification and click **Add Webhook**.
+1. Set **Payload URL** to the URL constructed above. Set **Content type**
+   to `application/json`. Select the events you would like to receive
+   notifications for, and click **Add Webhook**.
 
 {!congrats.md!}
 
-![](/static/images/integrations/github_webhook/004.png)
+![](/static/images/integrations/github_webhook/001.png)