[Perl/perl5] 6137bd: Correct typo in inline comment

[James E Keenan via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 6137bd7e7fb3d58a44ebeaa42209d3b1ac0a3869
      
https://github.com/Perl/perl5/commit/6137bd7e7fb3d58a44ebeaa42209d3b1ac0a3869
  Author: James E Keenan <jkee...@cpan.org>
  Date:   2021-06-21 (Mon, 21 Jun 2021)

  Changed paths:
    M Makefile.SH

  Log Message:
  -----------
  Correct typo in inline comment