BreakBeforeBraces: Attach ignored with trailing requires-expression of function

|  |  |
| --- | --- |
| Bugzilla Link | [48968](https://llvm.org/bz48968) |
| Version | trunk |
| OS | Linux |
| CC | @mkurdej,@JohelEGP |

## Extended Description 
.clang-format:
```
BreakBeforeBraces: Attach
```

Input and expected formatted result:
```C++
void f() requires requires { a; } {
  b;
  return c;
}
```

Actual output:
```C++
void f() requires requires { a; }
{
  b;
  return c;
}
```