Change the shortcut for Focus Sidebar to not interfere with text editing

[stan-janssen]

The existing <Ctrl> + Left would interfere when editing a filename.

Closes #2677.

[jeremypw]

See also elementary/code#1719. It would be good to agree on a common shortcut to switch to and from the sidebar. I think <Ctrl><Alt>Left <Ctrl><Alt>Right is more memorable on balance. Not sure how to make these shortcuts discoverable though.

[stan-janssen]

Thanks, I will update this PR to change the keyboard shortcut to <Ctrl><Alt>Left.

[stan-janssen]

(A thing that comes to mind: do people with a RTL (Right-To-Left) setting see the sidebar on the right side? And isn't a fixed directional-key shortcut confusing in that case? I assume that this won't be the only place this is encountered...)

[Dipanshusinghh]

Heiy everyone.
It’s great to see we are keeping the keyboard shortcuts consistent across the elementary ecosystem. Using Left and Right has felt quite natural while implementing it in Code (#1719)..
Regarding the RTL layout question, that's a very valid and interesting point! I imagine GTK might handle flipping directional keybindings automatically based on the system's text direction, but it's definitely something good to keep an eye on for the future..
Thanks for working on this

[stan-janssen]

I installed the Arabic language and took a look, and indeed the sidebar is on the right, and I still have to press <Ctrl><Alt>Left to get to it, which is not great. The same goes for navigating in column view by the way, the right arrow opens a new column (on the left).

I don't think this should block this PR, because it is not a regression to the current status, but I wonder if there is something in some of the underlying libraries that might help with abstracting this. If there isn't, perhaps directional arrow keys should only be used very cautiously in shortcuts.

[jeremypw]

I agree that dealing with RTL locales should be dealt with but can be done in another PR. It should be simple enough to alter the actions depending on the StateFlagsof the window (DIR_RTL or not).

[jeremypw]

This works as expected, thanks. I think that we should change the corresponding <Ctrl>Right shortcut as well though to maintain consistency?