Hide Markdown block titles

[asitemade4u]

Hi, this is a feature request, not a bug report.

Currently, when parsing Markdown including check boxes, the extension shows Markdown titles as directories. This is great.

But when all check boxes under a "directory"/Markdown title are checked, there should also be an option to hide the enclosing "directory".

As an illustration, here is what my Markdown To-Do sidebar list looks like:

Satisfying to know you've accomplished a lot of work, but not very efficient visually...

[h9h]

Hi, great extension!
This pull-request would hide the branches with 0 todos;
#11