For questions about the syntax highlighting performed inside code blocks on Stack Exchange sites.

Stack Exchange uses Prettify, a JavaScript library, for syntax highlighting of code blocks across the network.

Improvements to the highlighting for any specific language are most readily obtained by submitting patches to prettify's Google Code project, then (once the patches are accepted) requesting that SE update to a revision of Prettify that includes them.

For information on available languages and how to use syntax highlighting, see
What is syntax highlighting and how does it work?