Add support for CUDA source files

[jtmr05]

Summary 💡

It seems that .cu source files are simply ignored currently.

Motivation 🔦

No response

[spenserblack]

Hi! Would you mind using our new language request template? That would help us gather more info (like whether or not we can add support).

[jtmr05]

done

[spenserblack]

Thanks!