Rename quic::kMaxPacketSize to quic::kMaxOutgoingPacketSize

As part of cl/242197597, QUIC now has separate values for maximum incoming and outgoing packet sizes. This CL renames the constant to be clearer.

gfe-relnote: constant rename, no functional impact
PiperOrigin-RevId: 242708648
Change-Id: I3f440ba44b9c12394026116aaecdd2c166cc63b6
diff --git a/quic/core/quic_error_codes.h b/quic/core/quic_error_codes.h
index bbdb13f..9954134 100644
--- a/quic/core/quic_error_codes.h
+++ b/quic/core/quic_error_codes.h
@@ -118,7 +118,7 @@
   QUIC_DECRYPTION_FAILURE = 12,
   // There was an error encrypting.
   QUIC_ENCRYPTION_FAILURE = 13,
-  // The packet exceeded kMaxPacketSize.
+  // The packet exceeded kMaxOutgoingPacketSize.
   QUIC_PACKET_TOO_LARGE = 14,
   // The peer is going away.  May be a client or server.
   QUIC_PEER_GOING_AWAY = 16,