Makefile grammar for function call separator syntax

[Alex Ross]

The , needs a syntax grammar

Originally from @pouyakary in microsoft/vscode#132473

[Pouyā Kāry ✨]

@alexr00 thanks for the issue, I implemented this in the #11, hope to be merged soon.

[Alexander Fadeev]

@alexr00 @pouyakary I did it guys fcc4e92.