Can't parse into BigInt

[carpetdev]

The following fails for me:

JSON.parse("1", BigInt)
# ERROR: ArgumentError: applyeach not applicable for `JSON.LazyValue{String}` with JSON type = `JSONTypes.NUMBER`

Note that it works in JSON3.jl:

typeof(JSON3.parse("1", BigInt))
# BigInt

[quinnj]

This issue will be fixed by JuliaServices/StructUtils.jl#38

The root cause is that BigInt and BigFloat are mutable structs in Julia, so StructUtils.structlike() returns true for them. This causes StructUtils to route them to makestruct (which tries to iterate over struct fields) instead of lift (which handles primitive value conversion).

The fix adds structlike(::Type{BigInt}) = false and structlike(::Type{BigFloat}) = false to StructUtils, which will automatically fix this issue in JSON.jl without any changes needed here.