Bad identation of “for“ trait bounds

At the moment, the code is indented as
```rust
fn f<T>(v: &T)
where
    T: Zero,
for <'a> &'a T: <Output=&'a T>
```
while the correct indentation is
```rust
fn f<T>(v: &T)
where
    T: Zero,
    for <'a> &'a T: <Output=&'a T>
```
(It does not happen if “for“ is on the first line.)