improvement proposal for third party Borgmatic documentation

[Gustav74]

In section "Useful commands" --> "Break lock"¶

In the documentation the command
docker compose exec borgmatic-mailcow borg break-lock [e-mail]:mailcow
is used.

This requires the knowledge of username and storage path and you have to deal with the ports if youre using different than the standard ports.

Command
docker compose exec borgmatic-mailcow borgmatic borg break-lock
seems to be more elegant as it uses the already stored config.

reference: Borgmatic Docs How to section

cheers!