Add dockerignore extension

[eth0net]

This PR brings a new extension to support syntax highlighting for .dockerignore files.

[d1y]

I think it would be better if the dockerignore syntax highlighting could be put here https://github.com/d1y/dockerfile.zed :)

[eth0net]

I think it would be better if the dockerignore syntax highlighting could be put here https://github.com/d1y/dockerfile.zed :)

I also have a Docker Compose extension, would be better to combine them all but I originally avoided adding to your dockerfile extension since ideally it would be a new Docker extension. I had also forgotten about dockerignore at the time or I'd have just started on the combined one then 🤦🏻‍♀️

[maxdeviant]

@eth0net Did you still want to publish this extension now that git-firefly supports .dockerignore?

[eth0net]

Perhaps not, it might be worth condensing it into a whole docker extension at some point but for now let's close this.