Debian: fix HeeksCAD package description
Debian: fix HeeksCAD package description

Reported by litian: 
E: heekscad: description-starts-with-package-name
W: heekscad: extended-description-line-too-long
W: heekscad: extended-description-line-too-long

haiqiangwang/heekscad,satovey/heekscad,Funcan/heekscad,Funcan/heekscad,haiqiangwang/heekscad,satovey/heekscad,satovey/heekscad,haiqiangwang/heekscad,satovey/heekscad,haiqiangwang/heekscad,Funcan/heekscad,Funcan/heekscad