Add note about checking logged-in users with /exit q

Author: stopsopa

pages/ai/antigravity-cli.html

@@ -39,6 +39,7 @@ <h2>General stuff</h2>
               /clear
                 /context - current context usage
                 /usage   - check quota
+                # to see who is logged in just /exit and agy to see welcome message
               /fast    - I have to see if that could save some usage
               /model
               /resume  - browse and reuse past conversations