The documented examples do not work for RST code highlighting.
The <code> tool in the editor creates a
and that does not render with any highlighting at all.
There are questions on the board with users reporting the same for C as well as Python so this appears to be more than just one language.
Start a new wiki page, set it as a restructuredText markup, insert a code block, either from the example our using the tool. Click "view" and watch it NOT highlight. Click save and watch it render without highlighting.
Bug is seen by other Atlassian Employee: @aahmed