Describe the bug

When using a role in the REPL mode. the .exit role is not suggested in the auto-completion.

To Reproduce
Set a a role in aichat repl with .role <my-role>. Then Enter .exit and tabulate.

Expected behavior
the command .exit role should be suggested and unset the current role.

Environment (please complete the following information):

• os version: Debian 6.10.11-1
• aichat version: 0.23.0
• terminal version: kitty 0.35.2