Add more clarifications for mkdir
Add more clarifications for mkdir

that it's like `mkdir -p`
tbrowder/doc,dmaestro/doc,gfldex/doc,MasterDuke17/doc,stmuk/doc,perl6/doc,perl6/doc,stmuk/doc,perl6/doc,jonathanstowe/doc,stmuk/doc,dmaestro/doc,stmuk/doc,antquinonez/doc,tbrowder/doc,antquinonez/doc,antquinonez/doc,gfldex/doc,perl6/doc,MasterDuke17/doc,antquinonez/doc,jonathanstowe/doc,gfldex/doc,dmaestro/doc,MasterDuke17/doc,tbrowder/doc,dmaestro/doc,jonathanstowe/doc,dmaestro/doc,antquinonez/doc,tbrowder/doc,gfldex/doc,stmuk/doc,jonathanstowe/doc,MasterDuke17/doc,perl6/doc,jonathanstowe/doc,gfldex/doc