`A4-7-1`: integer data loss false positive erasing from container

### Affected rules
 - `A4-7-1`

### Description

Decrement cannot lead to wrap-around since the container is checked for emptiness.

### Example

```cpp
class container
{
    bool empty()
    {
        return num_items_ == 0;
    }

    void erase()
    {
        if (empty())
            return;

        num_items_--;
    }

    std::size_t num_items_ = 0;
};
```
