[Perl/perl5] 34315b: porting: fix item number on uncommitted files test

[Bruno Meneguele via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 34315b28685c433de750c356cfbd70b1c706abb9
      
https://github.com/Perl/perl5/commit/34315b28685c433de750c356cfbd70b1c706abb9
  Author: Bruno Meneguele <bme...@heredoc.io>
  Date:   2023-09-01 (Fri, 01 Sep 2023)

  Changed paths:
    M Porting/updateAUTHORS.pl

  Log Message:
  -----------
  porting: fix item number on uncommitted files test

Fix repeated number on item list in the guide presented to the user when
checking for uncommitted changes during `make_test`.