Merge branch 'lets-encrypt-docs' into 'master'

Update option to enforce HTTPS

See merge request gitlab-org/gitlab-ce!28232

doc/user/project/pages/lets_encrypt_for_gitlab_pages.md

@@ -145,8 +145,8 @@ Now that your certificate has been issued, let's add it to your Pages site:
 1. Visit your website at `https://example.com`.
 To force `https` connections on your site, navigate to your
-project's **Settings > Pages** and check **Force domains with SSL
-certificates to use HTTPS**.
+project's **Settings > Pages** and check **Force HTTPS (requires
+valid certificates)**.
 ## Renewal