[perl6/specs] e1da64: Kebab case superseded_by to superseded-by in S22

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/perl6/specs
  Commit: e1da64feaf3cb87130c860a492f9a4876f2dfe77
      
https://github.com/perl6/specs/commit/e1da64feaf3cb87130c860a492f9a4876f2dfe77
  Author: Jonathan Stowe <jns+...@gellyfish.co.uk>
  Date:   2015-11-01 (Sun, 01 Nov 2015)

  Changed paths:
    M S22-package-format.pod

  Log Message:
  -----------
  Kebab case superseded_by to superseded-by in S22