If the real part of the complex number \( (\,1-\cos\theta+2i\sin\theta\,)^{-1} \) is \( \dfrac{1}{5} \) for \( \theta \in (0,\pi) \), then the value of the integral \( \displaystyle\int\limits_{0}^{\theta}\sin x\,dx \) is equal to:
\( -1 \)
\( 2 \)
\( 1 \)
\( 0 \)