Set the left child. Also updates the new child's parent node. This
does not update the previous child.
Warning: If the node this is called on is a local variable, a stack pointer can be
escaped through newNode.parent. It's marked @trusted only for backwards compatibility.
Set the left child. Also updates the new child's parent node. This does not update the previous child.
Warning: If the node this is called on is a local variable, a stack pointer can be escaped through newNode.parent. It's marked @trusted only for backwards compatibility.
Returns newNode