[APO] Update faq.mdx (#16382)

Per https://developers.cloudflare.com/cache/how-to/edge-browser-cache-ttl/set-browser-ttl/

Author: nenizera

src/content/docs/automatic-platform-optimization/troubleshooting/faq.mdx

@@ -15,7 +15,7 @@ No. APO ignores Origin Cache Control for caching on the Edge, but APO serves ori
 
 ## Why are my browser cache control headers missing with APO?
 
-The browser cache control headers may be missing with APO if you set your browser to cache TTL to "respect existing headers." For example:
+The browser cache control headers may be missing with APO if you set your **Browser Cache TTL** to **Respect Existing Headers**. For example:
 
 ```sh
 curl --silent --verbose --output /dev/null https://example.com/ --header 'Accept: text/html' 2>&1 | grep cache-control
@@ -27,7 +27,7 @@ curl --silent --verbose --output /dev/null https://example.com/ --header 'Accept
 
 ## Is the stale-if-error directive still needed with APO?
 
-No, the stale-if-error directive is not needed because the feature is built into APO.
+No, the `stale-if-error` directive is not needed because the feature is built into APO.
 
 ## When I check the posts and homepage cache status, the response header shows `cf-cache-status: BYPASS`. Is APO working?