add index entry for is to classtut
add index entry for is to classtut

perl6/doc,dmaestro/doc,jonathanstowe/doc,antquinonez/doc,gfldex/doc,MasterDuke17/doc,perl6/doc,antquinonez/doc,gfldex/doc,antquinonez/doc,dmaestro/doc,tbrowder/doc,stmuk/doc,gfldex/doc,stmuk/doc,MasterDuke17/doc,perl6/doc,stmuk/doc,MasterDuke17/doc,gfldex/doc,jonathanstowe/doc,tbrowder/doc,gfldex/doc,tbrowder/doc,jonathanstowe/doc,antquinonez/doc,dmaestro/doc,stmuk/doc,MasterDuke17/doc,tbrowder/doc,perl6/doc,perl6/doc,antquinonez/doc,dmaestro/doc,jonathanstowe/doc,stmuk/doc,dmaestro/doc,jonathanstowe/doc