Trea http.ErrAbortHandler as broken pipe

```
ErrAbortHandler is a sentinel panic value to abort a handler.
While any panic from ServeHTTP aborts the response to the client, panicking with ErrAbortHandler also suppresses logging of a stack trace to the server's error log.
```

- CC - #1714
- similar to https://github.com/gorilla/handlers/pull/159/files
- Other PR: https://github.com/gin-gonic/gin/pull/2590

recovery.go

@@ -69,6 +69,9 @@ func CustomRecoveryWithWriter(out io.Writer, handle RecoveryFunc) HandlerFunc {
 						}
 					}
 				}
+				if errors.Is(err, http.ErrAbortHandler) {
+					brokenPipe = true
+				}
 				if logger != nil {
 					stack := stack(3)
 					httpRequest, _ := httputil.DumpRequest(c.Request, false)