[Perl/perl5] 8ab54e: Mark dowantarray() as deprecated

[Dagfinn Ilmari Mannsåker via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 8ab54e77a59c2f25aff25440e4592404cc8d8d72
      
https://github.com/Perl/perl5/commit/8ab54e77a59c2f25aff25440e4592404cc8d8d72
  Author: Dagfinn Ilmari Mannsåker <ilm...@ilmari.org>
  Date:   2023-02-10 (Fri, 10 Feb 2023)

  Changed paths:
    M embed.fnc
    M proto.h

  Log Message:
  -----------
  Mark dowantarray() as deprecated

This will make uses of the also-deprecated GIMME macro emit a
compile-time warning.