Debian: fix package description
Debian: fix package description

Reported by lintian:

E: heekscnc: description-starts-with-package-name
W: heekscnc: extended-description-line-too-long
W: heekscnc: extended-description-line-too-long
W: heekscnc: extended-description-line-too-long

FluffyMortain/heekscnc,JamieFBousfield/heekscnc,blakelyc/heekscnc,dnevels/heekscnc,singwina/heekscnc,BbiKkuMi/heekscnc,blakelyc/heekscnc,BbiKkuMi/heekscnc,hackendless/heekscnc,FluffyMortain/heekscnc,sangit/heekscnc,dnevels/heekscnc,masika/heekscnc,sangit/heekscnc,JamieFBousfield/heekscnc,singwina/heekscnc,elliotf/heekscnc,BbiKkuMi/heekscnc,singwina/heekscnc,blakelyc/heekscnc,AlanZheng/heekscnc,FluffyMortain/heekscnc,pyrotron/heekscnc,elliotf/heekscnc,masika/heekscnc,masika/heekscnc,hackendless/heekscnc,AlanZheng/heekscnc,pyrotron/heekscnc,singwina/heekscnc,Nurb432/heekscnc,hackendless/heekscnc,BbiKkuMi/heekscnc,AlanZheng/heekscnc,dnevels/heekscnc,Nurb432/heekscnc,ant-t/heekscnc,Nurb432/heekscnc,masika/heekscnc,dnevels/heekscnc,blakelyc/heekscnc,ant-t/heekscnc,ant-t/heekscnc,elliotf/heekscnc,pyrotron/heekscnc,elliotf/heekscnc,JamieFBousfield/heekscnc,hackendless/heekscnc,JamieFBousfield/heekscnc,sangit/heekscnc,Nurb432/heekscnc,sangit/heekscnc,ant-t/heekscnc,AlanZheng/heekscnc,pyrotron/heekscnc,FluffyMortain/heekscnc