VCL 4

[englercj]

Looks like there was a commit to add vcl 4 support but I don't think it is complete.

For example, vcl 4.0; is required as the first line but is not highlighted like I would expect.

This is a good guide for all the changes in VCL from 3 to 4:

https://www.varnish-cache.org/docs/4.0/whats-new/upgrading.html#changes-to-vcl