Set content type header for responses from Leptos so Firefox will be …

…happy, and because it's best practice

integrations/axum/src/lib.rs

@@ -773,8 +773,13 @@ async fn generate_response(
     if let Some(status) = res_options.status {
         *res.status_mut() = status
     }
+    // Set the Content Type headers on all responses. This makes Firefox show the page source
+    // without complaining
+    let headers = res.headers_mut();
+    headers.insert(http::header::CONTENT_TYPE,HeaderValue::from_str("text/html; charset=utf-8").unwrap(),
+    );
     let mut res_headers = res_options.headers.clone();
-    res.headers_mut().extend(res_headers.drain());
+    headers.extend(res_headers.drain());
 
     res
 }