[perl6/specs] 354bef: Clarify calling .cache more than once

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/perl6/specs
  Commit: 354bef8e9856f41c842d4d5e20c2695b8e20b6c0
      
https://github.com/perl6/specs/commit/354bef8e9856f41c842d4d5e20c2695b8e20b6c0
  Author: Tim Smith <tim.dolo...@gmail.com>
  Date:   2015-09-12 (Sat, 12 Sep 2015)

  Changed paths:
    M S07-lists.pod

  Log Message:
  -----------
  Clarify calling .cache more than once