import-mbox: Clarify List-ID format
import-mbox: Clarify List-ID format

The List-ID parameter must have a format of <list-name>@<domain> .
E.g. mylist@example.com

Make the user aware of that by clarifying the parameter's description.

Signed-off-by: Dimid Duchovny <ff96a2d69bb67a248e801292fcdba51a670f73f1@gmail.com>

jimjag/ponymail,Humbedooh/ponymail,quenda/ponymail,jimjag/ponymail,quenda/ponymail,jimjag/ponymail,Humbedooh/ponymail,quenda/ponymail,Humbedooh/ponymail,jimjag/ponymail