[perl6/specs] 4fa5b4: clarify that @$channel is not a combinator

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/perl6/specs
  Commit: 4fa5b487bb990cd8730dc6e3e598f6d9b397b082
      
https://github.com/perl6/specs/commit/4fa5b487bb990cd8730dc6e3e598f6d9b397b082
  Author: Larry Wall <la...@wall.org>
  Date:   2013-11-14 (Thu, 14 Nov 2013)

  Changed paths:
    M S17-concurrency.pod

  Log Message:
  -----------
  clarify that @$channel is not a combinator