feature: Allow adding a note to a tag

### Did you check the docs?

- [X] I have read the Grapple docs

### Is your feature request related to a problem? Please describe.

I use pretty granular scopes (sometimes git branch, sometimes not). When I use grapple a lot across branches, I may at times forget why I made a tag on a specific file / line.

### Describe the solution you'd like

If I could define a comment on a specific tag and view it with `require("grapple").open_tags()` that'd be really nice. And maybe edit the comment from the same viewer

### Describe alternatives you've considered

n/a

### Additional context

Would likely require editing `grapple.tag` and of course editing the buffer that displays `open_tags`. And it may also be a good idea to show the note in `Telescope grapple tags`, too

Start by reading grapple.tag and the code behind require("grapple").open_tags(), then inspect how the open_tags buffer is displayed and how Telescope grapple tags presents entries. Done means a tag can store a note, the note is visible in open_tags and Telescope grapple tags, and the viewer supports the requested note editing behavior.

Written by the indexing model from the issue text.