[Feature Request] Custom Codeblock formatting

Similarly to how we can inset custom emojis, we should be able to create pseudo-languages to be able to use to format the codeblock ( ``` ) feature in, for instance, one could create "```math" which would be like an extended version of ```diff, assigning * as blue, / as yellow, and have letters (variables) in orange, or ```pemdas where the would use red parintheses (And their variants), blue ^'s (exponents) but * and / would both be green, just as + and - would be yellow, reflecting which parts are done together...

But those are just the first two potential uses for such a feature,