[APO]Update verify-apo-works.mdx (#21757)

Option to confirm APO is up and running via a terminal.

Author: nenizera

src/content/docs/automatic-platform-optimization/get-started/verify-apo-works.mdx

@@ -20,6 +20,23 @@ You can check whether or not APO is working by verifying APO headers are present
 * `cf-edge-cache` | `cache, platform=wordpress`
   * The `cf-edge-cache` headers confirms the WordPress plugin is installed and enabled.
 
+In a terminal, use the following cURL. The header `'accept: text/html'` is important
+
+```sh
+curl -svo /dev/null -A "CF" 'https://example.com/' -H 'accept: text/html' 2>&1 | grep 'cf-cache-status\|cf-edge\|cf-apo-via'
+```
+
+```sh output
+< cf-cache-status: HIT
+< cf-apo-via: cache
+< cf-edge-cache: cache,platform=wordpress
+```
+
+As always, `cf-cache-status` displays if the asset hit the cache or was considered dynamic and served from the origin.
+
+- The `cf-apo-via` header returns the APO status for the given request.
+- The `cf-edge-cache` header means the WordPress plugin is installed and enabled.
+
 ## Verify the APO integration and WordPress integration work
 
 Open your WordPress site and publish a change. When the integration is working, the page is cached with `cf-cache-status: HIT` and `cf-apo-via: tcache`