Commit panel should be automatically focused when toggled via a key binding

[nathansobo]

I frequently show the commit panel with ctrl-9. In a situation where I am showing the panel for the first time, I think it makes sense to transfer focus to it so it can be used, even though there's a separate binding for toggling focus independently of visibility.

[smashwilson]

This would make ctrl-9 and ctrl-shift-9 identical when the panel is hidden. It also means you don't have a way to show the panel without focusing it.

I keep looking to the Tree View keybindings because I like preserving symmetry between the two, but honestly the bindings for show and focus there are a bit weird to me:

'.platform-darwin':
  'cmd-\\': 'tree-view:toggle'
  'cmd-k cmd-b': 'tree-view:toggle'
  'ctrl-0': 'tree-view:toggle-focus'

'.platform-win32, .platform-linux':
  'ctrl-\\': 'tree-view:toggle'
  'ctrl-k ctrl-b': 'tree-view:toggle'
  'alt-\\': 'tree-view:toggle-focus'

So toggle focus is ctrl-0, but only on Mac, and other than that they're \ bindings, and toggle visibility vs. focus is cmd vs ctrl on Mac and ctrl vs. alt on Windows and Linux... ? 🤔

Overall I'm tentatively okay with this because, honestly, I keep wanting it too. I do want to do what I can to keep the keybindings learnable, even for people who aren't using this every day, though.

[nathansobo]

Can we subtly massage the tree view bindings around ctrl-0 to make them blend in with the bindings for the commit panel. I'd like a pattern to emerge around using ctrl-# and ctrl-shift-# to toggle various panels in an intuitive way.

Maybe ctrl-# toggles focus, showing the panel if necessary (because you can't focus it if it isn't visible) and ctrl-shift-# toggles visibility (including for the tree view).

Then we consider the other tree view bindings to be legacy holdovers from a bygone era.

[smashwilson]

💯 Yeah, that sounds excellent to me.

[smashwilson]

This may be impacted by #629.