Fix typos in focus editor group commands (#81)

[CAESIUS-TIM]

fix #81

[MarcoIeni]

I would remove the word "group" because we call them just "editor" I think.

Also, what's the difference between previous and left in this context?

[CAESIUS-TIM]

previous also focuses left but in a cycle, meaning it will focus the rightmost window when you're on the leftmost.

It's just too powerful and different from vim shortcut.

If there is no need to change previous and next, I still recommend to change "move" into "focus" because it's confused with "move editor to another group", like workbench.action.moveEditorToLeftGroup.

[MarcoIeni]

meaning it will focus the rightmost window when you're on the leftmost

This seems like a "feature" to me 😅 but let's wait on @stevenguh to see if he has any preference. 👍

[stevenguh]

These makes sense to me in a first glance. which-key uses the the vscode naming

[MarcoIeni]

ok, merging than, thanks!