src/vs/workbench/contrib/notebook/browser/contrib/outline/notebookOutline.ts/OutlineEntry/icon
class OutlineEntry:	get icon(): ThemeIcon {
		return this.isExecuting && this.isPaused ? executingStateIcon :
			this.isExecuting ? ThemeIcon.modify(executingStateIcon, 'spin') :
				this.cell.cellKind === CellKind.Markup ? Codicon.markdown : Codicon.code;
	}