### What it does
Checks the doc comments of publicly visible functions that
may panic and warns if there is no `# Panics` section.

### Why is this bad?
Documenting the scenarios in which panicking occurs
can help callers who do not want to panic to avoid those situations.

### Examples
Since the following function may panic it has a `# Panics` section in
its doc comment:

```
/// # Panics
///
/// Will panic if y is 0
pub fn divide_by(x: i32, y: i32) -> i32 {
    if y == 0 {
        panic!("Cannot divide by 0")
    } else {
        x / y
    }
}
```