make clash less likely

packages/svelte/test/runtime/samples/attribute-custom-element-inheritance/_config.js

@@ -2,6 +2,6 @@ export default {
 	skip_if_ssr: true,
 	skip_if_hydrate: true,
 	html: `
-		<my-custom-element>Hello World!</my-custom-element>
+		<my-custom-inheritance-element>Hello World!</my-custom-inheritance-element>
 	`
 };

packages/svelte/test/runtime/samples/attribute-custom-element-inheritance/main.svelte

@@ -27,7 +27,7 @@
 
 	class Extended extends MyCustomElement {}
 
-	window.customElements.define('my-custom-element', Extended);
+	window.customElements.define('my-custom-inheritance-element', Extended);
 </script>
 
-<my-custom-element camelCase={{ text: 'World' }} text="!" />
+<my-custom-inheritance-element camelCase={{ text: 'World' }} text="!" />