improve the GitHub Server subdomain isolation config description (#2667)

* improve the GitHub Server subdomain isolation config description

* Update modules/administration-guide/partials/proc_applying-the-github-oauth-app-secret.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

---------

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

Author: vinokurig

modules/administration-guide/partials/proc_applying-the-github-oauth-app-secret.adoc

@@ -36,15 +36,15 @@ metadata:
   annotations:
     che.eclipse.org/oauth-scm-server: github
     che.eclipse.org/scm-server-endpoint: __<github_server_url>__ <2>
-    che.eclipse.org/scm-github-disable-subdomain-isolation: "__<true_or_false>__" <3>
+    che.eclipse.org/scm-github-disable-subdomain-isolation: true <3>
 type: Opaque
 stringData:
   id: __<GitHub_OAuth_Client_ID>__ <4>
   secret: __<GitHub_OAuth_Client_Secret>__ <5>
 ----
 <1> The {prod-short} namespace. The default is `{prod-namespace}`.
 <2> This depends on the GitHub product your organization is using: When hosting repositories on GitHub.com or GitHub Enterprise Cloud, omit this line or enter the default `https://github.com`. When hosting repositories on GitHub Enterprise Server, enter the GitHub Enterprise Server URL.
-<3> This line is only added for GitHub Enterprise Server. To disable subdomain isolation, set this to `"true"`. To enable subdomain isolation, set this to `"false"`.
+<3> This line is only added for GitHub Enterprise Server with disabled link:https://docs.github.com/en/enterprise-server/admin/configuration/hardening-security-for-your-enterprise/enabling-subdomain-isolation#about-subdomain-isolation[subdomain isolation] option. If the subdomain isolation option is enabled on GitHub Enterprise Server, you must either omit this annotation or set it to `false`.
 <4> The *GitHub OAuth Client ID*.
 <5> The *GitHub OAuth Client Secret*.