add syntax highlight for code block in markdown

[bruceunx]

this app is excellent, but the code in markdown has no syntax highlight, maybe add later.

[rifkybujana]

Hi, working on this on the next few version

[rifkybujana]

Tried to work on this using regex, but the performance was very poor. Will look into other solutions. Meanwhile, I'll keep this issue open in case anyone has any input or suggestions. Will take more time before able to add this feature yet.