Function JSONNumber.opAssign

Support assignment of numbers.

void opAssign (
  JSONNumber other
) nothrow @nogc @trusted;

void opAssign (
  double value
) nothrow @nogc @safe;

void opAssign (
  long value
) nothrow @nogc @safe;

void opAssign (
  std.bigint.BigInt value
) nothrow @nogc @safe;