Update secrets.en-us.md (#26057)

Present documentation does not capture that secrets are only visible if
ACTIONS are enabled for a repository. This PR adds a short note

Author: eeyrjmr

docs/content/doc/usage/secrets.en-us.md

@@ -18,7 +18,7 @@ menu:
 # Secrets
 
 Secrets allow you to store sensitive information in your user, organization or repository.
-Secrets are available on Gitea 1.19+.
+Secrets are available on Gitea 1.19+ and are only visible in 1.20+ when ACTIONS are enabled 
 
 # Naming your secrets