Spread the info about shortcuts

[shpaass]

It's awesome that YAFC has shortcuts. Now we just need to tell the users which shortcuts exist. I think an addition to the Docs of the repository would be a good start.

[veger]

To kick this off with the shortcuts I know about: There are a few mentioned in the startup tips.

[shpaass]

Yes, I think a good start would be to expand the startup tips with the new shorcuts from #154

[DaleStan]

I don't know how much it counts, but when you hover over a button with a right-click shortcut, a tooltip appears. Here are two of them, though you'll only see one at a time in real life.

There are no hints for Enter or Escape, though.

[shpaass]

Criterion of ticket completion:
Either me or someone else needs to go over all the shortcuts and check that they are explained at least somewhere somehow.