[perl6/specs] 15083d: Add discussion note about immutable iterators.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/perl6/specs
  Commit: 15083d900888ea1c428e3a03c480ccc83dba1e37
      
https://github.com/perl6/specs/commit/15083d900888ea1c428e3a03c480ccc83dba1e37
  Author: pmichaud <pmich...@pobox.com>
  Date:   2015-06-12 (Fri, 12 Jun 2015)

  Changed paths:
    M S07-glr-draft.pod

  Log Message:
  -----------
  Add discussion note about immutable iterators.