fix(playground): always set language to trigger the tree-sitter langu…

…age onChange event (#12)

* Update index.html

set default language to `yaml` by `js`, because use html set the default select value  does't trigger  the `tree-sitter.js` onChange event

* fix: 🐛 fix problem select change event does not trigger macos

docs/index.html

@@ -117,3 +117,9 @@ <h4>Tree</h4>
   src="https://code.jquery.com/jquery-3.3.1.min.js"
   crossorigin="anonymous">
 </script>
+<script>
+  let select = document.getElementById('language-select')
+  select.value = 'yaml'
+  select.dispatchEvent(new Event('change'))
+</script>
+