Actually literate programming might be a tool to get you syntax highlighting back. You could write one block of code in one language and the other one in anothe

Actually literate programming might be a tool to get you syntax highlighting back. You could write one block of code in one language and the other one in another language and make one include the other in some place. Both blocks annotated to be their specific language, inside the prose. Emacs for example syntax highlights each block according to its corresponding programming language. It also allows you to edit blocks in separate buffers. Another way could be to switch the syntax highlighting of ones editor temporarily, but then syntax of the surrounding prose and other block might interfere.