Update content/actions/reference/workflow-syntax-for-github-actions.md

Co-authored-by: Martin Lopes <54248166+martin389@users.noreply.github.com>

Author: varunsridharan

content/actions/reference/workflow-syntax-for-github-actions.md

@@ -546,7 +546,7 @@ jobs:
 
 `docker://{host}/{image}:{tag}`
 
-A Docker image in a public registry.
+A Docker image in the {% data variables.product.prodname_github_container_registry %}.
 
 ```yaml
 jobs: