Poor line breaking around `@unchecked Sendable`

[jrose-signal]

public class ProtocolAddress: ClonableHandleOwner<SignalMutPointerProtocolAddress>, @unchecked Sendable {
  // …
}

This admittedly-lengthy inheritance clause gets formatted as

public class ProtocolAddress: ClonableHandleOwner<SignalMutPointerProtocolAddress>, @unchecked
  Sendable
{
}

which is definitely not the best place for a line break. The general principle here is probably to keep attributes with the thing they're attached to when the attachee isn't at the start of a line.

[allevato]

I don't think we've touched inheritance list entries since the ability to put attributes to them was added to the language, so this is definitely unintentional behavior.

The fix should be straightforward enough: we should add open/close grouping tokens around the entire entry, encapsulating both the attribute and the type name.