[Perl/perl5] bc08f9: perldelta.pod - document changes to UNIVERSAL.pm

[Yves Orton via perl5-changes]

  Branch: refs/heads/yves/delta_universal_import
  Home:   https://github.com/Perl/perl5
  Commit: bc08f9be931e57531e87ffcd92ceaa6b62dad060
      
https://github.com/Perl/perl5/commit/bc08f9be931e57531e87ffcd92ceaa6b62dad060
  Author: Yves Orton <demer...@gmail.com>
  Date:   2023-07-19 (Wed, 19 Jul 2023)

  Changed paths:
    M pod/perldelta.pod
    M pod/perldiag.pod

  Log Message:
  -----------
  perldelta.pod - document changes to UNIVERSAL.pm

We now define a UNIVERSAL::import and UNIVERSAL::unimport
this explains why and what the consequences. Also tweaks
the existing perldiag documentation of it.