QUIC - minor clean up of comments per wtc' comments for the CL:

net/quic/quic_sent_packet_manager.cc

Index: net/quic/quic_sent_packet_manager.cc
diff --git a/net/quic/quic_sent_packet_manager.cc b/net/quic/quic_sent_packet_manager.cc
index d92140ad896468c667f54babcb60935482bff69b..f2eb6d3a17b7e1c17d9c74aec2a5825415dbe954 100644
--- a/net/quic/quic_sent_packet_manager.cc
+++ b/net/quic/quic_sent_packet_manager.cc
@@ -173,8 +173,8 @@ void QuicSentPacketManager::HandleAckForSentPackets(
     }
 
     if (IsAwaitingPacket(received_info, sequence_number)) {
-      // Remove any packets not being tracked by the send algorithm, allowing
-      // the high water mark to be raised if necessary.
+      // Remove any rtt only packets less than or equal to the largest observed,
+      // since they will not produce an RTT measurement.
       if (QuicUnackedPacketMap::IsForRttOnly(it->second)) {
         it = MarkPacketHandled(sequence_number, delta_largest_observed);
       } else {