src/vs/editor/contrib/hover/browser/contentHover.ts/HoverResult/filter
class HoverResult:	public filter(anchor: HoverAnchor): HoverResult {
		const filteredMessages = this.messages.filter((m) => m.isValidForHoverAnchor(anchor));
		if (filteredMessages.length === this.messages.length) {
			return this;
		}
		return new FilteredHoverResult(this, this.anchor, filteredMessages, this.isComplete);
	}