parser: Check for comma after parameter in function call

[f1ypopper]

[BuggieBot]

Hello!

One or more of the commit messages in this PR do not match the Jakt code submission policy, please check the lint_commits CI job for more details on which commits were flagged and why. Please do not close this PR and open another, instead modify your commit message(s) with git commit --amend and force push those changes to update this PR.

[f1ypopper]

Hey @jntrnr can you please review the PR again?

[sophiajt]

@f1ypopper - looks like you'll need to follow the submission guidelines that BuggieBot links to.

Also, you should add a test to show that the error is working

[AtkinsSJ]

Closed as this is a change for the now-gone Rust-based compiler. Feel free to port your changes to the new compiler, if they're not already added, and open a new PR. :^)