pub fn append_child(
doc: &mut BaseDocument,
parent: NodeId,
child: NodeId,
) -> Result<NodeId>Expand description
parent.appendChild(child), returning the child.
The child is detached from any current parent first, which is what makes “move to the end of the same parent” behave.
A runtime that supports custom elements must run its upgrade step after
this call: insertion is when connectedCallback is due, and constructing a
guest object is not something this crate can do.