Support for BigInt literals

Just a heads-up—BigInts are coming to Chrome at end of next month.

I tried inputting 1234n in Observable in Chrome Canary to try this, and the parser won’t take it. Looking forward to playing with this when ready!

Our general philosophy (aligned with Acorn’s) is to wait for proposals to reach stage 4. That said, we’re willing to make some exceptions for certain stage 3 proposals, such as dynamic import, if there’s strong demand and decent browser support.

support added. example here: