Update intro.pod6
Update intro.pod6

Perl6 -> Perl 6
section name changed to Sentence case.
tbrowder/doc,tbrowder/doc,tbrowder/doc,stmuk/doc,perl6/doc,perl6/doc,perl6/doc,MasterDuke17/doc,stmuk/doc,stmuk/doc,stmuk/doc,stmuk/doc,perl6/doc,MasterDuke17/doc,tbrowder/doc,perl6/doc,MasterDuke17/doc,MasterDuke17/doc