add shitty JSX namespace fix for our website

Author: slorber

website/types.d.ts

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// This is a bad workaround to make our site typecheck under React 19
+// We run our site with "skipLibCheck=false", unfortunately some libraries
+// are still using the global JSX namespace, that has been removed in v19
+// See https://react.dev/blog/2024/04/25/react-19-upgrade-guide#the-jsx-namespace-in-typescript
+declare namespace JSX {
+  // eslint-disable-next-line @typescript-eslint/no-empty-interface
+  interface Element {}
+  interface IntrinsicElements {
+    [elemName: string]: unknown;
+  }
+  // eslint-disable-next-line @typescript-eslint/no-empty-interface
+  interface ElementClass {}
+}