[Perl/perl5] e6145c: locale.c: Fix typo

[Karl Williamson via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: e6145c96910698f2944584752f4fcde8e1ba3365
      
https://github.com/Perl/perl5/commit/e6145c96910698f2944584752f4fcde8e1ba3365
  Author: Karl Williamson <k...@cpan.org>
  Date:   2024-01-22 (Mon, 22 Jan 2024)

  Changed paths:
    M locale.c

  Log Message:
  -----------
  locale.c: Fix typo

This #define has a trailing underscore