Proposal: Enhance the visual representation of Code blocks (via Extensions, or opt-in standard)

[farangkao]

The only visual part i currently don't like of pi, is the representation of code blocks.
so i asked my agent if this is changeable ,according to his research, it's not currently doable via an extension,
only by modifying the pi code directly, which isn't ideal.
i've still tested it, and here some screenshots of how it could look like:

So my proposal would be to either allow extensions to override the respresentation (if this is already possible, please give me some pointers) or adapt an enhanced display (maybe as opt-in) for code blocks.

Since code-blocks is a vital part of coding works, it would be really appreciated.