PDD 19: Explain :method :multi(_)
PDD 19: Explain :method :multi(_)

I didn't expect :multi to need to add the type of the invocant.  So
let's add an explanation to the first place I looked for an answer.

parrot/parrot,tkob/parrot,tkob/parrot,gagern/parrot,gagern/parrot,tkob/parrot,gitster/parrot,parrot/parrot,gitster/parrot,FROGGS/parrot,gitster/parrot,FROGGS/parrot,youprofit/parrot,FROGGS/parrot,parrot/parrot,youprofit/parrot,parrot/parrot,gitster/parrot,youprofit/parrot,FROGGS/parrot,tkob/parrot,tkob/parrot,FROGGS/parrot,tkob/parrot,gitster/parrot,FROGGS/parrot,gagern/parrot,FROGGS/parrot,tkob/parrot,youprofit/parrot,youprofit/parrot,gitster/parrot,youprofit/parrot,gitster/parrot,gagern/parrot,FROGGS/parrot,gagern/parrot,youprofit/parrot,youprofit/parrot,parrot/parrot,tkob/parrot,gagern/parrot,gagern/parrot