Support generic parameters in "extract function" refactoring

[Undin]

Current "extract function" implementation doesn't add type parameters and their bounds for generic arguments into function signature.
It would be great to support it.

fn foo<T: Default>() -> T {
    <selection>T::default()</selection>
}

Expected:

fn foo<T: Default>() -> T {
    bar()
}

fn bar<T: Default>() -> T {
    T::default()
}

Actual:

fn foo<T: Default>() -> T {
    bar()
}

fn bar() -> T {
    T::default()
}

[t-kameyama]

I will work on this issue.

[Undin]

Implemented in #2197