Markdown Force Disable Syntax Highlighting

Hi,

It would be nice if when displaying Markdown READMEs in the repository overview, users can disable syntax highlighting altogether for code blocks.

I've been trying to find a way to do this to no avail in the following Bitbucket documentation.
https://confluence.atlassian.com/display/BITBUCKET/Display+README+text+on+the+overview

I only need something really simple like the following example. In the example, the flag lang-none forces no syntax highlighting.

Contents of README.md

```lang-none
$ even though this looks like a shell session due to the dollar signs
$ do not try to guess the language or perform any syntax highlighting
```