src/vs/editor/contrib/hover/browser/contentHover.ts/ContentHoverController/_addLoadingMessage
class ContentHoverController:	private _addLoadingMessage(result: IHoverPart[]): IHoverPart[] {
		if (this._computer.anchor) {
			for (const participant of this._participants) {
				if (participant.createLoadingMessage) {
					const loadingMessage = participant.createLoadingMessage(this._computer.anchor);
					if (loadingMessage) {
						return result.slice(0).concat([loadingMessage]);
					}
				}
			}
		}
		return result;
	}