Fix HTML in sitemap. Add DOCTYPE, language, and a title.

main.js

@@ -104,7 +104,14 @@ async function main() {
 			</url>
 	`;
 	let sitemap_html = `
-		<html><body>
+		<!DOCTYPE html>
+		<html lang="en">
+		<head>
+			<title>
+				Sitemap for Hyperling
+			</title>
+		</head>
+		<body>
 			<strong>Special Pages</strong>
 			<ul>
 				<li>