In the official github flavored markdown docs they show how we can use fences to mark code blocks, and optionally we can supply a language identifier, such as
```ruby
require 'redcarpet'
markdown = Redcarpet.new("Hello World!")
puts markdown.to_html
```
Is there a language identifier for Objective C? I've searched and cannot find a reference.
Furthermore, is there a list of all supported language identifiers that can be used in github markdown?