### What it does
Looks for blocks of expressions and fires if the last expression returns
`()` but is not followed by a semicolon.

### Why is this bad?
The semicolon might be optional but when extending the block with new
code, it doesn't require a change in previous last line.

### Example
```
fn main() {
    println!("Hello world")
}
```
Use instead:
```
fn main() {
    println!("Hello world");
}
```