Fix log message text

A log message said AppendAckFrame... It should say AppendIetfAck...
Fixed.

gfe-relnote: N/A is a change in a v99 log message
PiperOrigin-RevId: 237438072
Change-Id: Iaf570aed75eaf9bb93457de6730c93e8cf8778bb

quic/core/quic_framer.cc

diff --git a/quic/core/quic_framer.cc b/quic/core/quic_framer.cc
index 03cfcd6..2ffb762 100644
--- a/quic/core/quic_framer.cc
+++ b/quic/core/quic_framer.cc
@@ -1092,7 +1092,8 @@
         break;
       case ACK_FRAME:
         if (!AppendIetfAckFrameAndTypeByte(*frame.ack_frame, writer)) {
-          QUIC_BUG << "AppendAckFrameAndTypeByte failed: " << detailed_error();
+          QUIC_BUG << "AppendIetfAckFrameAndTypeByte failed: "
+                   << detailed_error();
           return 0;
         }
         break;