Add note for how all CE applies to EE

doc/development/changelog.md

@@ -114,6 +114,11 @@ the `--ee` option:
 bin/changelog --ee 'Hey DZ, I added a feature to GitLab!'
 ```
 
+NOTE: **Note:**
+All entries in the `CHANGELOG.md` file apply to all editions of GitLab.
+Changelog updates are based on a common [GitLab codebase](https://gitlab.com/gitlab-org/gitlab/),
+and are mirrored without proprietary code to [GitLab FOSS](https://gitlab.com/gitlab-org/gitlab-foss/) (also known as GitLab Community Edition).
+
 At this point the script would ask you to select the category of the change (mapped to the `type` field in the entry):
 
 ```plaintext