Merge pull request #5868 from kiendang/extract-rename-class

Fix incorrect formula name from file name

Library/Homebrew/dev-cmd/extract.rb

@@ -142,7 +142,7 @@ module Homebrew
 
     # The class name has to be renamed to match the new filename,
     # e.g. Foo version 1.2.3 becomes FooAT123 and resides in Foo@1.2.3.rb.
-    class_name = name.capitalize
+    class_name = Formulary.class_s(name.to_s)
     versioned_name = Formulary.class_s("#{class_name}@#{version}")
     result.gsub!("class #{class_name} < Formula", "class #{versioned_name} < Formula")