The value of \( \displaystyle \int_{-\pi}^{\pi} \frac{2y(1+\sin y)}{1+\cos^2 y}\,dy \) is:
\( \dfrac{\pi}{2} \)
\( \pi^2 \)
\( \dfrac{\pi^2}{2} \)
\( 2\pi^2 \)