Add TypeScriptReact syntax test file

tests/syntax-tests/highlighted/TypeScriptReact/app.tsx

@@ -0,0 +1,35 @@
+import * as React from "react";
+import { HelloComponent } from "./hello";
+import { NameEditComponent } from "./nameEdit";
+
+export const App = () => {
+  const [name, setName] = React.useState("defaultUserName");
+  const [editingName, setEditingName] = React.useState("defaultUserName");
+
+  const loadUsername = () => {
+    setTimeout(() => {
+      setName("name from async call");
+      setEditingName("name from async call");
+    }, 500);
+  };
+
+  React.useEffect(() => {
+    loadUsername();
+  }, []);
+
+  const setUsernameState = () => {
+    setName(editingName);
+  };
+
+  return (
+    <>
+      <HelloComponent userName={name} />
+      <NameEditComponent
+        initialUserName={name}
+        editingName={editingName}
+        onNameUpdated={setUsernameState}
+        onEditingNameUpdated={setEditingName}
+      />
+    </>
+  );
+};