Updates cache-tag note

Author: angelampcosta

src/content/docs/cache/how-to/purge-cache/purge-by-tags.mdx

@@ -43,6 +43,7 @@ When your content reaches our edge network, Cloudflare:
 * The `Cache-Tag` HTTP header must only contain UTF-8 encoded characters.
 * Spaces are not allowed in cache-tags.
 * Case does not matter. For example, `Tag1` and `tag1` are considered the same.
+* Cache-tags set by a Worker override those from the Origin, meaning that only the tags applied by the Worker will be effective.
 
 ## Purge using cache-tags