Calendar preview shows correct files for each dot

[TKDKid1000]

Fixes #1798 with a stable dot hover detection system.

The issue was that, if you hovered a day on the calendar preview, you would only be able to see the first file from that day. This allows you to hover over a specific dot to see a specific file from that day. I wrote an initial implementation, then looked and saw lizhuoran1019@3afb3c7, which seemed to be a bit similar to mine, and theirs had some flaw in it which mine also did. The people there suggested using data- tags, which I tried, and it now seems to work quite reliably.

There is still an issue where, if you move your mouse around on the dots, multiple previews stack up back to back. I have an idea on how to fix this, but I don't know the Obsidian events API enough to be able to close a hover preview. If someone knows that, I would appreciate it, but this should resolve #1798 for now. Each dot now corresponds to an individual note created that day.

[vrouilhac]

Any update on this? This fix would be highly appreciated 👍

[TKDKid1000]

I think I read somewhere that the owner basically stopped working on this project to go work on Datacore, even though the most recent commit was less than 2 weeks ago. I obviously can't know for sure though, and I'll leave this PR open until I get something definitive telling me to do otherwise.