extensions/markdown-language-features/src/features/previewContentProvider.ts/MarkdownContentProvider/computeCustomStyleSheetIncludes
class MarkdownContentProvider:	private computeCustomStyleSheetIncludes(resourceProvider: WebviewResourceProvider, resource: vscode.Uri, config: MarkdownPreviewConfiguration): string {
		if (!Array.isArray(config.styles)) {
			return '';
		}
		const out: string[] = [];
		for (const style of config.styles) {
			out.push(`<link rel="stylesheet" class="code-user-style" data-source="${escapeAttribute(style)}" href="${escapeAttribute(this.fixHref(resourceProvider, resource, style))}" type="text/css" media="screen">`);
		}
		return out.join('\n');
	}