Need to update vscode-fastly-vcl extension to support declaring custom functions in VCL with parameters

[AndreGuerrero]

Hi Team,

A new release of VCL is going to support declaring custom functions with parameters. Example below:

sub testfunc(STRING var.a, STRING var.b) STRING {...}

Currently, when declaring functions in this manner in VS Code, this extension does not recognizes it as valid and raise errors.
I'm opening this ticket to get this feature recognized in the extension.

Thank you!