[Markdown] support for links to folder

[irvnriir]

Would be good to make the Preview handle links to folders, for example open them with executable defined in settings .

I see no point in downloading another program to use it as .md viewer, adding all features to VSCode's Preview is much more logical .

[mjbvz]

The preview already reveals links to folders in the explorer. This should work for link both in markdown editors and in the markdown preview

Being able to customize this behavior is a better fix for an extension

[irvnriir]

It started working after update . though it doesn't support cases when the folder isn't a part of the workspace .