Make clone URL use current page's host (#22808)

Follow #21986

Even if the ROOT_URL is incorrect, the clone URL on the UI should be
correct.

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Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

templates/repo/clone_script.tmpl

@@ -17,7 +17,14 @@
 		const btn = isSSH ? sshBtn : httpsBtn;
 		if (!btn) return;
 
-		const link = btn.getAttribute('data-link');
+		let link = btn.getAttribute('data-link');
+		if (link.startsWith('http://') || link.startsWith('https://')) {
+			// use current protocol/host as the clone link
+			const url = new URL(link);
+			url.protocol = window.location.protocol;
+			url.host = window.location.host;
+			link = url.toString();
+		}
 		for (const el of document.getElementsByClassName('js-clone-url')) {
 			el[el.nodeName === 'INPUT' ? 'value' : 'textContent'] = link;
 		}