Remove B type param: Follow ups (#1789)

Co-authored-by: Jonas Platte <[email protected]>
Co-authored-by: Michael Scofield <[email protected]>

examples/prometheus-metrics/src/main.rs

@@ -8,8 +8,7 @@
 //! ```
 
 use axum::{
-    extract::MatchedPath,
-    http::Request,
+    extract::{MatchedPath, Request},
     middleware::{self, Next},
     response::IntoResponse,
     routing::get,
@@ -94,7 +93,7 @@ fn setup_metrics_recorder() -> PrometheusHandle {
         .unwrap()
 }
 
-async fn track_metrics<B>(req: Request<B>, next: Next<B>) -> impl IntoResponse {
+async fn track_metrics(req: Request, next: Next) -> impl IntoResponse {
     let start = Instant::now();
     let path = if let Some(matched_path) = req.extensions().get::<MatchedPath>() {
         matched_path.as_str().to_owned()