Completion based on either VMODs or VCC config files
Create a .varnishls.toml file in your workspace directory
# .varnishls.toml in your workspace dir
main_vcl = "vg/varnish.vcl" # path to the main (root) vcl file varnish uses in the workspace
vmod_paths = ["/usr/lib/varnish-plus/vmods/"] # paths to directories containing your vmods (.so binaries)
vcc_paths = ["/usr/src/varnish-cache/lib/"] # paths to directories containing vcc files (vmod definition files)
vcc_paths will be used in place of vmods_paths if it exists.
VCC are varnish-spesific "header"-files that contains syntax and docs for vmods.
Create a directory where you dump all the VCC files that match the vmods you are using and point the vcc_paths there.