[css-text-3] Markup fix

Author: fantasai

css-text-3/Overview.bs

@@ -5615,7 +5615,7 @@ Identifying the Content Writing System</h2>
 	when no other is specified.
 	IANA maintains a database of various languages’ default writing systems
 	via the <code>Suppress-Script</code> field in its
-	<a href="https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry">language subtag registry</a
+	<a href="https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry">language subtag registry</a>
 	for this purpose.
 
 	Note: More advice on language tagging can be found in