Set prism theme for Markdown code?

I know this thread is rather old, but I came across it while trying to solve the problem from the original post: Selecting a Prism theme instead of using the default one.

After moving on, I came across a good solution in an older thread, and figured it may help anyone else that ends up here later: How to enable Prism on DT 3.5? - #17 by MosCool_Noel

This doesn’t utilize the extension checkbox in the DEVONthink preferences, but it is a working way to set alternate Prism themes for rendering markdown files in DEVONthink.