Move experimental.pm to upstream=blead

Experience has thought that almost all changes to experimental.pm come
from core, hence it's easier for maintenance if we move its upstream to
blead, and sync the CPAN version with that.

Author: Leont

Porting/Maintainers.pl

@@ -436,7 +436,7 @@ package Maintainers;
     'experimental' => {
         'DISTRIBUTION' => 'LEONT/experimental-0.036.tar.gz',
         'SYNCINFO'     => 'jkeenan on Sat Jul 19 12:50:08 2025',
-        'FILES'        => q[cpan/experimental],
+        'FILES'        => q[dist/experimental],
         'EXCLUDED'     => [qr{^xt/}],
     },