To be clear, this is declaring that `$textNode.traversingMethod()` always yields an empty collection—a breaking change with respect to 1.9.0—for compatibility with current state of 2.0 beta.

Instead of declaring text nodes to be invalid input for all traversing methods that may or may not work.

When we've never promised that they work, it just happens that they have up to 2.0.

This seems disastrous.