=htc improve error messages

akka-http-core/src/main/scala/akka/http/engine/rendering/RenderSupport.scala

@@ -68,13 +68,13 @@ private object RenderSupport {
     def onNext(elem: ByteString): List[ByteString] = {
       sent += elem.length
       if (sent > length)
-        throw new InvalidContentLengthException(s"HTTP message had declared Content-Length $length but entity chunk stream amounts to more bytes")
+        throw new InvalidContentLengthException(s"HTTP message had declared Content-Length $length but entity data stream amounts to more bytes")
       elem :: Nil
     }
 
     override def onTermination(e: Option[Throwable]): List[ByteString] = {
       if (sent < length)
-        throw new InvalidContentLengthException(s"HTTP message had declared Content-Length $length but entity chunk stream amounts to ${length - sent} bytes less")
+        throw new InvalidContentLengthException(s"HTTP message had declared Content-Length $length but entity data stream amounts to ${length - sent} bytes less")
       Nil
     }
   }

akka-http-core/src/test/scala/akka/http/engine/rendering/ResponseRendererSpec.scala

@@ -141,14 +141,14 @@ class ResponseRendererSpec extends FreeSpec with Matchers with BeforeAndAfterAll
         the[RuntimeException] thrownBy {
           HttpResponse(200, entity = Default(ContentTypes.`application/json`, 10,
             source(ByteString("body123")))) should renderTo("")
-        } should have message "HTTP message had declared Content-Length 10 but entity chunk stream amounts to 3 bytes less"
+        } should have message "HTTP message had declared Content-Length 10 but entity data stream amounts to 3 bytes less"
       }
 
       "one chunk and incorrect (too small) Content-Length" in new TestSetup() {
         the[RuntimeException] thrownBy {
           HttpResponse(200, entity = Default(ContentTypes.`application/json`, 5,
             source(ByteString("body123")))) should renderTo("")
-        } should have message "HTTP message had declared Content-Length 5 but entity chunk stream amounts to more bytes"
+        } should have message "HTTP message had declared Content-Length 5 but entity data stream amounts to more bytes"
       }
 
     }