Correctly handle multi-line aliases attempt #3.

Each line needs command chars adding, not just the first one.

Change-Id: I95976dcdf102744e25ed29ea99ff9dd6b32b44ef
Reviewed-on: http://gerrit.dmdirc.com/3554
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager