The title might be a bit misleading. As far as I know 'less' does not support script highlight (please correct me if I'm wrong). However I did find out that vim has a built-in script that allows you to use it as less.
So here's a very simple solution, add an alias to your ~/.bashrc pointing the vim script:
You can see from the screenshot bellow that the file is open as read-only and not modifications are allowed. Some of 'less' commands (like “q” to quit) are also replicated.