[Feature request]

**Is your feature request related to a problem? Please describe.**
I noticed for many files the code runner button can tell what the file type is open and perform the right action based on that. But markdown does nothing. Its understandable that markdown files are not code but its frustrating when I see a play button but it doesn't open the markdown preview for me if I'm viewing a markdown content in edit mode.

**Describe the solution you'd like**
Having the code runner button open markdown preview :)