[Perl/perl5] 139cae: readline ARGV: don't try to open '|-' or '-|' and ...

[Tony Cook via perl5-changes]

  Branch: refs/heads/smoke-me/tonyc/21176-no-ARGV-fork
  Home:   https://github.com/Perl/perl5
  Commit: 139cae90dded94a8d22f5b210fa91ec14559499a
      
https://github.com/Perl/perl5/commit/139cae90dded94a8d22f5b210fa91ec14559499a
  Author: Tony Cook <t...@develop-help.com>
  Date:   2023-07-03 (Mon, 03 Jul 2023)

  Changed paths:
    M doio.c
    M embed.fnc
    M embed.h
    M pod/perldiag.pod
    M proto.h
    M t/io/argv.t

  Log Message:
  -----------
  readline ARGV: don't try to open '|-' or '-|' and warn

This has no effect on in-place editing nor on the <<>> operator.

Later modified to ignore leading/trailing space when checking
the name.

Fixes #21176