Make full value of cell visible in tooltips/hints

[dseomn]

The proposed change

Currently if a cell in the song list or queue is truncated because the value is longer than the width of the column, it's possible to hover over it to get a tooltip/hint to see more of the value. But if the distance from the left edge of the column to the right edge of the screen isn't large enough to fit the full value, the tooltip is truncated too. Some possible solutions, I don't have much of an opinion about which ones are better/worse:

1. For a multi-valued column like genre, use newlines instead of commas to separate multiple values in the tooltip. (I.e., reduce the chance that the tooltip would hit the right edge of the screen.)
2. Move the left edge of the tooltip so that the full value fits.
3. Wrap lines in the tooltip.

Benefits of this change

It would be easier to see the full value of a tag in the song list or queue without needing to go to the edit tags dialog.

Any issues this might cause

I'm not sure, I don't know much about how tooltips work in GTK.

[declension]

2. sounds hard, given what Gtk.Tooltip offers
3. and 3. if done bluntly wouldn't be too hard, but depending on exact screen layout sounds hard too.

But happy if someone comes up with a PR for this...