Format h2 response_fields (rustfmt)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: MagicalTux

src/h2/conn.rs

@@ -570,7 +570,11 @@ impl H2Conn {
 
 /// Build the HPACK field list for a response from the shared response-header
 /// rules (`:status` first, hop-by-hop dropped, `server` defaulted).
-fn response_fields(status: StatusCode, headers: &Headers, server: Option<&str>) -> Vec<HeaderField> {
+fn response_fields(
+    status: StatusCode,
+    headers: &Headers,
+    server: Option<&str>,
+) -> Vec<HeaderField> {
     crate::proto::response_fields(status, headers, server)
         .iter()
         .map(|(n, v)| HeaderField::new(n, v))