Allow empty directories to be selected as categories

[joeySeal]

For example
If I create a child directory inside of /Notes that does not contain a *.md file the notes app will not allow me to select it as a category. There are situations where I might create a new directory(category) from my desktop and put other file types in it and would like to use it as a notes category as well.

[korelstar]

Please see #413 (comment) for an instruction on how to use a new category. Notes will use the existing folder, if you type its name into the category field. Does this work for you?

[joeySeal]

@korelstar yes that works but it seems like an unnecessary extra step

[korelstar]

Which part of that is "unnecessary extra" for you - compared to assigning an existing category?

[joeySeal]

See attached screenshot, unless I am overlooking something. I would have to type out the entire path if I want to use an existing directory which contains no *.md files

[korelstar]

I see. I think we really can improve that and show also empty directories in auto-completion.