[Perl/perl5] 4622e1: [doc] Update IO::Handle synopsis

[Elvin Aslanov via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 4622e102066ac6c21fa38a6622b883eed7e7ed9e
      
https://github.com/Perl/perl5/commit/4622e102066ac6c21fa38a6622b883eed7e7ed9e
  Author: Elvin Aslanov <rwp.prim...@gmail.com>
  Date:   2022-08-30 (Tue, 30 Aug 2022)

  Changed paths:
    M dist/IO/lib/IO/Handle.pm

  Log Message:
  -----------
  [doc] Update IO::Handle synopsis

Add `my` to examples for better practice.