Add per policy options

Author: maxvp

src/content/partials/cloudflare-one/gateway/add-block-page.mdx

@@ -12,6 +12,7 @@ import { Markdown } from "~/components";
 4. Choose your block behavior:
    - **Use account-level block setting**: Use the global block page setting configured in your account settings. The global setting can be the default Gateway block page, an [HTTP redirect](/cloudflare-one/policies/gateway/block-page/#redirect-to-a-block-page), or a [custom Gateway block page](/cloudflare-one/policies/gateway/block-page/#customize-the-block-page).
    - **Override account setting with URL redirect**: Redirect users with a `307` HTTP redirect to a URL you specify on a policy level.
-5. Select **Save policy**.
+5. (Optional) If your account-level block page setting uses a custom Gateway block page, you can turn on **Add an additional message to your custom block page when traffic matches this policy** to add a custom message to your custom block page when traffic is blocked by this policy. This option will replace the **Message** field.
+6. Select **Save policy**.
 
 Depending on your settings, Gateway will display a block page in your users' browsers or redirect them to a specified URL when they are blocked by this policy.