# description
Abstract base for document nodes with labels.

# $comment
This is a mixin-style base type for document nodes that participate in
author-facing numbering, captions, and cross-references. It centralizes the
common label metadata and whether an identifier was generated automatically.

# properties.idAutomatically.description
Whether the identifier should be automatically updated.

# properties.idAutomatically.$comment
When true, the `id` has been generated from the node's label or other
document context and should not be encoded to author-facing source formats
as a persistent identifier.

# properties.labelAutomatically.description
Whether the label should be automatically updated.