Fix up and refactor util/perl-nbsp.p6
Fix up and refactor util/perl-nbsp.p6

Sometimes the script would replace the "6" in "Perl 6" with nothing for
whatever reason. That no longer happens. A filename can now be passed to
the script so it'll only check that file for any instances of "Perl 6"
using regular spaces.

tbrowder/doc,tbrowder/doc,perl6/doc,MasterDuke17/doc,MasterDuke17/doc,perl6/doc,perl6/doc,tbrowder/doc,perl6/doc,tbrowder/doc,MasterDuke17/doc,perl6/doc,MasterDuke17/doc