We have indeterminateness of type
0/0,
i.e. limit for the numerator is
$$\lim_{x \to 0^+}\left(\cos{\left(x \right)} - 1\right) = 0$$
and limit for the denominator is
$$\lim_{x \to 0^+} \frac{1}{\cot{\left(x \right)}} = 0$$
Let's take derivatives of the numerator and denominator until we eliminate indeterninateness.
$$\lim_{x \to 0^+}\left(\left(\cos{\left(x \right)} - 1\right) \cot{\left(x \right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \left(\cos{\left(x \right)} - 1\right)}{\frac{d}{d x} \frac{1}{\cot{\left(x \right)}}}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{\sin{\left(x \right)} \cot^{2}{\left(x \right)}}{\cot^{2}{\left(x \right)} + 1}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \frac{1}{\cot^{2}{\left(x \right)} + 1}}{\frac{d}{d x} \left(- \frac{1}{\sin{\left(x \right)} \cot^{2}{\left(x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{\left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{\left(- \frac{2 \cot^{2}{\left(x \right)} + 2}{\sin{\left(x \right)} \cot^{3}{\left(x \right)}} + \frac{\cos{\left(x \right)}}{\sin^{2}{\left(x \right)} \cot^{2}{\left(x \right)}}\right) \left(\cot^{2}{\left(x \right)} + 1\right)^{2}}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{\left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{\left(- \frac{2 \cot^{2}{\left(x \right)} + 2}{\sin{\left(x \right)} \cot^{3}{\left(x \right)}} + \frac{\cos{\left(x \right)}}{\sin^{2}{\left(x \right)} \cot^{2}{\left(x \right)}}\right) \left(\cot^{2}{\left(x \right)} + 1\right)^{2}}\right)$$
=
$$0$$
It can be seen that we have applied Lopital's rule (we have taken derivatives with respect to the numerator and denominator) 2 time(s)