which-update: use Formula#full_name
which-update: use Formula#full_name

bfontaine/homebrew-command-not-found,bfontaine/homebrew-command-not-found,Homebrew/homebrew-command-not-found,lordlycastle/homebrew-command-not-found,lordlycastle/homebrew-command-not-found,Homebrew/homebrew-command-not-found