Update docs/user/icl/local-vc-authentication.inc

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: SimonEntholzer

docs/user/icl/local-vc-authentication.inc

@@ -90,6 +90,7 @@ VCS access tokens
 
 The tokens for student repositories are automatically created, and provided to the student via the code button dialog.
 
+.. warning:: Never share your access tokens or commit them to version control. Treat tokens like passwords. If a token is compromised, revoke it immediately and create a new one.
 Instructors can create HTTP access tokens for repository access in Artemis.
 They are created in the account settings and are used in place of passwords for Git over HTTPS.
 For every student's exercise, Artemis automatically generates an access token, only associated with the repository of this particular exercise.