Fix minor typo in AsyncHttpClientConfig.java (AsyncHttpClient#1534)

Author: stv8

client/src/main/java/org/asynchttpclient/AsyncHttpClientConfig.java

@@ -164,7 +164,7 @@ public interface AsyncHttpClientConfig {
   /**
    * Return the list of {@link RequestFilter}
    *
-   * @return Unmodifiable list of {@link ResponseFilter}
+   * @return Unmodifiable list of {@link RequestFilter}
    */
   List<RequestFilter> getRequestFilters();