Multi-line Fn supertraits are indented improperly

Multi-line supertraits appear to be insufficiently indented:

trait Foo:
    Fn(
    ReallyLongTypeName,
    ReallyLongTypeName,
    ReallyLongTypeName,
    ReallyLongTypeName,
) -> ReallyLongTypeName
{
}

I'd prefer the later lines to be indented an extra level:

trait Foo:
    Fn(
        ReallyLongTypeName,
        ReallyLongTypeName,
        ReallyLongTypeName,
        ReallyLongTypeName,
    ) -> ReallyLongTypeName
{
}

(playground example)

Thank you!

Reproduce the formatting difference using the linked Rust Playground example and compare the input with the expected output in the issue. No source file or test is named, so locate the rustfmt formatting entry point for multi-line function-trait supertraits, then add coverage showing the later lines receive the extra indentation.