ChartType
ChartType =
"bar"|"line"|"pie"|"area"|"scatter"|"unknown"
Defined in: src/core/document-model/types.ts:833
ECMA-376 Part 1 §21.2 — the kind of a DrawingML chart. A chart is referenced
from a w:drawing (a:graphicData uri=…/chart → c:chart r:id) and its data
lives in a separate chart part (e.g. word/charts/chart1.xml). The parsed
Chart is keyed by that relationship id and supplied to the renderer
alongside the body (mirroring image bytes), so ChartBlock only carries
the ref.