Subject: [quicwg/base-drafts] a6a720: Use contains() (#3015)

From: ianswett <[email-masked]>
Date: Tue, 10 Sep 2019 15:05:08 -0700

Branch: refs/heads/master
  Home:   https://github.com/quicwg/base-drafts
  Commit: a6a7203c7dff9dae6408f8cfbb008e14c1aeaf9a
      https://github.com/quicwg/base-drafts/commit/a6a7203c7dff9dae6408f8cfbb008e14c1aeaf9a
  Author: ianswett <[email-masked]>
  Date:   2019-09-10 (Tue, 10 Sep 2019)

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

  Log Message:
  -----------
  Use contains() (#3015)

Per @martinthomson suggestion, use contains() instead of the implicit check.

Fixes #2569 
An alternative to #2987