[Python-checkins] [python/cpython] 951e5f: update doc

[GitHub]

  Branch: refs/heads/bpo-30014-selectors-modify-speedup
  Home:   https://github.com/python/cpython
  Commit: 951e5f7bf993640f4d47ab9b8f57aadec1d74fd3
      https://github.com/python/cpython/commit/951e5f7bf993640f4d47ab9b8f57aadec1d74fd3
  Author: Giampaolo Rodola <g.rodola at gmail.com>
  Date:   2017-06-07 (Wed, 07 Jun 2017)

  Changed paths:
    M Doc/whatsnew/3.7.rst

  Log Message:
  -----------
  update doc