Print meaningful message on missing formula

Add an import statement needed for `MissingFormula` to be found.

Fixes #8538.

Reported-by: Nate Whetsell <nathan.whetsell@gmail.com>

Library/Homebrew/cli/named_args.rb

@@ -3,6 +3,7 @@
 require "cask/cask_loader"
 require "delegate"
 require "formulary"
+require "missing_formula"
 
 module Homebrew
   module CLI