[Feature Request] Multi-levels of label selection to avoid overlapping when there are too many labels.

[unifreak]

I'm totally keyboard driven, so I use labels a lot when inside Sioyek. One issue of labels is that when there are too many, they will look like this and making it hard to recognize:

This image shows the case when labeling code snippets, there seems lots of unnecessary labels for leading spaces, causing overlapping labels. But even for regular paragraphs, this can happen, too.

So my thought is, can we have multi-levels labels for selection? Something like:

1. First we label paragraphs for selection with one letter;
2. Then we label words inside selected paragraph with another one letter;

Of course, one letter can only distinct between 26 (or 52 if case-sensitive) labels, so this is not ideal, but that's the general idea. One workable solution might be group every 26 or 52 words as one chunk for level one selection.

This sounds like a lot of works, just a thought. Also thanks for creating Sioyek, love it!