proposal: syscall/js: recognize JS bigint primitives in Value.Type

[jcbhmr]

Proposal Details

Right now there's no TypeBigint for Value.Type() to return if the type is a bigint primitive (typeof v returns "bigint" in js)

I propose adding support for this new primitive, similar to the JS symbol primitive and how that is implemented in syscall/js right now -- it can be completely opaque to Go code.

[ianlancetaylor]

CC @golang/js

[Zxilly]

I agree with this proposal, maybe we could try to provide a way to convert to math/big?