A heading of a layout tree, with its level.
public sealed class LayoutHeading : LayoutNode
ISO 32000-2 §14.8.4.5, Table 366.
kind:method, kind:property, kind:ctor. Press Esc to clear.LevelGets the heading's level: n for Hn; for H, the number of Sect elements it is nested in within its Document or DocumentFragment, at least 1; 0 for a Title, the title of a document or high-level division, above every numbered level.