Docs: Spamcheck is free, add EE requirement

doc/user/admin_area/reporting/spamcheck.md

@@ -4,7 +4,7 @@ group: Distribution
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Spamcheck anti-spam service **(PREMIUM SELF)**
+# Spamcheck anti-spam service **(FREE SELF)**
 
 > [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/6259) in GitLab 14.8.
 
@@ -12,6 +12,8 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 developed by GitLab originally to combat rising amount of spam in GitLab.com,
 and later made public to be used in self-managed GitLab instances.
 
+Spamcheck [contains obfuscated, non-free code](https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/6259#note_726605397) which only is available in the GitLab Enterprise Edition. You can [migrate from the Community Edition](../../../update/package/convert_to_ee.md), and use the Free tier. 
+
 ## Enable Spamcheck
 
 Spamcheck is only available for package-based installations: