Subject: [quicwg/base-drafts] c02d91: Merge ECN text in Section 7

From: Martin Thomson <[email-masked]>
Date: Wed, 06 Jan 2021 01:47:29 -0800

Branch: refs/heads/only-one-ecn
  Home:   https://github.com/quicwg/base-drafts
  Commit: c02d91f4a1a0a5c1295b91cc6c07a454c491b408
      https://github.com/quicwg/base-drafts/commit/c02d91f4a1a0a5c1295b91cc6c07a454c491b408
  Author: Martin Thomson <[email-masked]>
  Date:   2021-01-06 (Wed, 06 Jan 2021)

  Changed paths:
    M draft-ietf-quic-transport.md

  Log Message:
  -----------
  Merge ECN text in Section 7

This is my best stab at it.

Closes #4521.