Add built-in formatting and previewing

[Srihan-Yeleswarapu]

In VS Code, if you open a .md file, and then do Ctrl+Shift+V, it opens a preview of the MD file. In VS Code, if you open a .ipynb file, it shows it in the clean ipynb format, and if you double click on a cell, you can edit it. Try seeing if you can add some features to support this, because it would really help me.

[crynta]

.md files already have a preview functionality (via right-clicking in the file explorer), but I don't think .ipynb is the right option here