Add rule to check access on RegExp capture groups

[ajafff]

If a regular expression literal is statically known, we can check accessed capture groups of the match result.

const r1 = /(.)(.)/;
const m1 = r1.exec(someString)!;
console.log(
  m1[0], // always valid
  m1[1], // allowed
  m1[2], // allowed
  m1[3], // not allowed
  m1.groups, // not allowed
);

const r2 = /(?<foo>.)/;
const m2 = re.exec(someString)!;
console.log(
  m2[0], // always valid
  m2[1], // not allowed
  m2.groups!.foo, // allowed
  m2.groups.bar, // not allowed
);

This may need control flow analysis to reliably tell where the match result came from and if the regular expression is a known literal.

Upstream feature request: microsoft/TypeScript#32098