pub fn section(header: &ViewHandle, content: &ViewHandle) -> ViewHandleExpand description
Section(header:) { … }.
The header is a value parameter of generic type, so it travels indirectly —
x0 holds the address of the AnyView word, not the word. It is @in, i.e.
consumed, so the handle is retained and forgotten rather than dropped here.
Generic order is Section<Parent, Content, Footer>; this overload pins
Footer == EmptyView, leaving two metadata words and two witness tables.