doc: fix description what mt2exm -c does

Continuous mode (-c) is not tied to delivery (-D), it also
applies to message streams.

References: DESK-3640

Author: jengelh

doc/gromox-mt2exm.8

@@ -38,9 +38,9 @@ rules, and folders in the MT stream will be ignored altogether, which also
 implies that \-B is ignored.
 .TP
 \fB\-c\fP
-Continuous operation mode. Errors during the delivery of a message are
+Continuous operation mode. Errors during the import of a message are
 reported, but mt2exm will continue with importing more messages. The default is
-to exit after reporting a delivery error. Only useful with \fB\-D\fP.
+to exit after reporting a delivery error.
 .TP
 \fB\-p\fP
 Show properties in detail (enhances \fB\-t\fP).