Matcher props must be required in the modifier's body

```
interface IRatingHintProps {
hint?: string;
}
```

Before:
``` tsx
export const withHint = withBemMod(
'Rating',
{ hint: '*' },
Rating => props => (


{props.hint && }

);
```

After:
``` tsx
export const withHint = withBemMod(
'Rating',
{ hint: '*' },
Rating => props => (




);
```

`props.hint` must be required in the body context, because modifier applied already and we don't need to check existing of matched prop.