Merging `EffectGen`'s Iterator into `Effect` Prototype to Simplify `yield*` Syntax

Effect.gen(function* (_) {
  yield* _(Ef.log("Hello, world"));

  yield* _( // This pipe is non-sense, it's just for sake of an piping example.
    Ef.succeed("Hello, world"),
    Ef.tap(Ef.log),
    Ef.as(0)
  );
})
// becomes
Effect.gen(function* () {
  yield* Ef.log("Hello, world");

  yield* pipe(
    Ef.succeed("Hello, world"),
    Ef.tap(Ef.log),
    Ef.as(0)
  );
})

Effect.gen(function* (_) {
  yield* _(Ef.log("Hello, world"));

  yield* _( // This pipe is non-sense, it's just for sake of an piping example.
    Ef.succeed("Hello, world"),
    Ef.tap(Ef.log),
    Ef.as(0)
  );
})
// becomes
Effect.gen(function* () {
  yield* Ef.log("Hello, world");

  yield* pipe(
    Ef.succeed("Hello, world"),
    Ef.tap(Ef.log),
    Ef.as(0)
  );
})