extensions/markdown-language-features/src/markdownExtensions.ts/getContributedMarkdownItPlugins
	function getContributedMarkdownItPlugins(
		contributes: any,
		extension: vscode.Extension<any>
	): Map<string, Thenable<(md: any) => any>> {
		const map = new Map<string, Thenable<(md: any) => any>>();
		if (contributes['markdown.markdownItPlugins']) {
			map.set(extension.id, extension.activate().then(() => {
				if (extension.exports && extension.exports.extendMarkdownIt) {
					return (md: any) => extension.exports.extendMarkdownIt(md);
				}
				return (md: any) => md;
			}));
		}
		return map;
	}