Better formatting with proc-scoped type aliases

[mikex-oss]

What's hard to do? (limit 100 words)

With #1050, you can have proc scoped type aliases.

But the DSLX formatter seems to shove the types and channels into one big blob and does not preserve user inserted line breaks.

proc Foo {
    type Bar = bits[32];

    bar: chan<Bar> out;
    baz: chan<Bar> in;

    config(bar: chan<Bar> out, baz: chan<Bar> in) { (bar, baz) }

    init { () }

    next(state: ()) {  }
}

is reformatted to

proc Foo {
    type Bar = bits[32];
    bar: chan<Bar> out;
    baz: chan<Bar> in;

    config(bar: chan<Bar> out, baz: chan<Bar> in) { (bar, baz) }

    init { () }

    next(state: ()) {  }
}

Current best alternative workaround (limit 100 words)

Adding a comment like //Channels at least helps delineate where the channel declarations start.

Your view of the "best case XLS enhancement" (limit 100 words)

Preserve user line breaks which can be helpful for signifying different conceptual clusters of code.