Double dash parameters don't flow correctly when using multiple script execution

[xt0rted]

Given the following:

dotnet r build test publish:* -- --configuration release

It will be expanded to:

dotnet r build --configuration release
dotnet r test --configuration release
dotnet r publish:* --configuration release

This results in the --configuration release portion being treated as two script names due to the missing -- between the script name and parameter list. I don't think this was an issue prior to adding multiple script execution but it definitely is now.