Update draft-ietf-quic-transport.md

Co-Authored-By: Martin Thomson <mt@lowentropy.net>

draft-ietf-quic-transport.md

@@ -3518,7 +3518,7 @@ use the following steps on receiving an ACK frame to validate ECN.
   This step detects any erroneous network remarking from ECT(0) to ECT(1) (or
   vice versa).
 
-Another special case is when all packets are indicatd as CE marked,
+Another special case is when all packets are marked ECN-CE,
 independtly of the initial codepode used, including Not-ECT. In this case
 it could be a network element overwriting the ECN field of all packets and
 thereby potentially concealing actual congestion information. Especially,