Add missing require in `dev-cmd/irb`.
Add missing require in `dev-cmd/irb`.

nandub/brew,konqui/brew,sjackman/homebrew,EricFromCanada/brew,Homebrew/brew,vitorgalvao/brew,JCount/brew,nandub/brew,EricFromCanada/brew,Homebrew/brew,JCount/brew,nandub/brew,Homebrew/brew,konqui/brew,JCount/brew,claui/brew,sjackman/homebrew,claui/brew,claui/brew,JCount/brew,EricFromCanada/brew,vitorgalvao/brew,vitorgalvao/brew,Homebrew/brew,EricFromCanada/brew,MikeMcQuaid/brew,sjackman/homebrew,konqui/brew,konqui/brew,MikeMcQuaid/brew,sjackman/homebrew,claui/brew,nandub/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,vitorgalvao/brew