Update http-core/src/main/scala/org/apache/pekko/http/impl/engine/http2/RequestParsing.scala

Author: He-Pin

http-core/src/main/scala/org/apache/pekko/http/impl/engine/http2/RequestParsing.scala

@@ -189,6 +189,7 @@ private[http2] object RequestParsing {
       try {
         subStream.initialHeaders.headerParseErrorDetails match {
           case Some(details) =>
+            // header errors already found in decompression
             BadRequest(details, subStream.streamId)
           case None =>
             val incomingHeaders = subStream.initialHeaders.keyValuePairs.toIndexedSeq