Add negative tags

[rio-raimundo]

This PR adds support for 'negative' tags when choosing which whole notes should be reviewed.

This was added because it is sometimes useful to exclude notes with a specific tag from review.

For example, I use spaced repetition to review notes associated with academic papers, tagged with #paper. However, I sometimes create these notes before reading the paper so that I can link them to other notes; in these cases they are tagged #unread and I do not want them to show up for review, but I also want them to keep the paper tag.

Now you can ignore a subset of notes by adding a 'negative' tag to the settings, formatted like -#unread (shown above). This gives users more options if they want to review notes using an existing tag system, instead of having to manually cultivate a tag just for reviewed notes.

[[Edit: I rewrote this to better document the changes and explain why they're useful]]

[ronzulu]

Hi @bitesizing, thanks for this.

Since you implemented this, the code base (beta) has changed considerably, primarily due to:
Feat 878 Refactor code to support diff methods of storing the scheduling info, and diff SR algorithms #1006

1. So I think we need to extract the logic that you implemented and move to a new spot, possibly something in the new SettingsUtil class. There is an existing method filterForNoteReviewTag that may be of interest.

The latest beta code is available at:
Beta release of outstanding PRs #1011

2. We also should add a couple of unit test cases.

3. I wonder if there are better terms positive/negative. For example perhaps exclusion tag conveys the meaning better than negative.

[rio-raimundo]

Hi @ronzulu, thanks for this! It seems like you've done loads of impressive work on the repo:)

Just to be clear because I'm quite new to contributing, are the changes to the code base that you mentioned reflected in the newest pushes to the master branch? I.e., can I just fork the repo and reintegrate my changes into the new structure. Or do I need to access the source code for the beta release directly?

[ronzulu]

Hi @bitesizing , thanks for the feedback :-)

This is new territory for me as well actually. The changes to the code base haven't been integrated into the master repository https://github.com/st3v3nmw/obsidian-spaced-repetition. Unfortunately the project owner @st3v3nmw has been out of contact, so we don't know when this would happen.

I've merged in a few different outstanding PRs into the "beta code" on my repository. I was able to do that without involving the PR contributor as those changes affected different parts of the code.

So this is the first time your question has come up. I guess there are 2 options:

1. Wait and see when Stephen is back on board and has integrated other PRs including [FEAT] Refactor code to support diff methods of storing the scheduling info, and diff SR algorithms #878 into st3v3nmw/obsidian-spaced-repetition. and then git update your branch from it.
2. Fork from my repository, and make the necessary changes to incorporate your work. I would then merge your changes into my "beta branch".

If you choose 2, let me know if you have trouble as no one has needed to do this before.

Cheers
Ronny