Implement RegExp d flag

[dirkdev98]

ECMASCript feature

When the d flag is present, re.exec() includes the matched indices. When the RegExp constructor is used, RegExp.prototype.hasIndices should be correctly set.

See the spec (step 6 & 34) and MDN .

Example code

/a/d.exec("a");
// [
//   'a',
//   index: 0,
//   input: 'a',
//   groups: undefined,
//   indices: [ [ 0, 1 ], groups: undefined ]
// ]

new RegExp("a", "d").hasIndices;
// true

[dirkdev98]

I'd like to work on this 😃