Describe the intervals on which each function $f$ in exercises is continuous. At each point where $f$ fails to be continuous, use limits to determine the type of discontinuity and any left-or right-continuity.
$$
f(x)=\left\{\begin{aligned}
x^{2}-3 x-1, & \text { if } x \neq-2 \\
3, & \text { if } x=-2
\end{aligned}\right.
$$