fix: always close tags when namespace is foreign (#12623)

Author: dummdidumm

packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js

@@ -95,7 +95,7 @@ export function RegularElement(node, context) {
 		);
 	}
 
-	if (!VoidElements.includes(node.name) && namespace !== 'foreign') {
+	if (!VoidElements.includes(node.name) || namespace === 'foreign') {
 		state.template.push(b.literal(`</${node.name}>`));
 	}
 

packages/svelte/tests/runtime-legacy/samples/attribute-casing-foreign-namespace/_config.js

@@ -1,7 +1,9 @@
 import { test } from '../../test';
 
 export default test({
-	skip: true, // TODO: needs fixing
+	// TODO: needs fixing. Can only be fixed once we also support document.createElementNS-style creation of elements
+	// because the $.template('...') approach has no option to preserve attribute name casing
+	skip: true,
 
 	html: `
 		<page horizontalAlignment="center">