Fix #98: Redirect to main branch when only lang slug is present (#167)

* Add docs/$lang.ts file for redirection

Author: utkarshpant

app/routes/docs.$lang.ts

@@ -0,0 +1,5 @@
+import { redirect, type LoaderFunctionArgs } from "@remix-run/node";
+export async function loader({ params }: LoaderFunctionArgs) {
+    const { lang, ref } = params;
+    return !ref ? redirect(`/docs/${lang}/main`) : null;
+}