### What it does
Checks for usage of if expressions with an `else if` branch,
but without a final `else` branch.

### Why is this bad?
Some coding guidelines require this (e.g., MISRA-C:2004 Rule 14.10).

### Example
```
if x.is_positive() {
    a();
} else if x.is_negative() {
    b();
}
```

Use instead:

```
if x.is_positive() {
    a();
} else if x.is_negative() {
    b();
} else {
    // We don't care about zero.
}
```