Improved Dockerfile compatibility
Improved Dockerfile compatibility

line 28 : modified the regexp to also match if the optional '#' caracter is present to comment the line, like it was by default on my Debian:9 official based image.
line 28 : modified the regexp by adding the 'g' end caracter, just for better readability for beginners like me.
line 31 : modified the order between option '-i' and the regexp argument, just for better readability for beginners like me.
thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io