option parser: check for extra named args

Library/Homebrew/cli/parser.rb

Library/Homebrew/cmd/--version.rb

Library/Homebrew/cmd/analytics.rb

Library/Homebrew/cmd/cat.rb

Library/Homebrew/cmd/commands.rb

Library/Homebrew/cmd/config.rb

Library/Homebrew/cmd/diy.rb

Library/Homebrew/cmd/gist-logs.rb

Library/Homebrew/cmd/leaves.rb

Library/Homebrew/cmd/log.rb

Library/Homebrew/cmd/sh.rb

Library/Homebrew/cmd/switch.rb

Library/Homebrew/cmd/tap.rb

Library/Homebrew/dev-cmd/bump-formula-pr.rb

Library/Homebrew/dev-cmd/bump-revision.rb

Library/Homebrew/dev-cmd/create.rb

Library/Homebrew/dev-cmd/extract.rb

Library/Homebrew/dev-cmd/install-bundler-gems.rb

Library/Homebrew/dev-cmd/man.rb

Library/Homebrew/dev-cmd/release-notes.rb