docs: Fix rendering of code blocks in list items

Created by: mrnugget

@unknwon and I found out that a bug (https://github.com/russross/blackfriday/issues/484) in our Markdown renderer, blackfriday, causes list items to be rendered incorrectly if they contain code blocks with a language.

The workaround is to remove the language from the code blocks. We lose syntax highlighting, but we gain readable lists.

Example: