fix(vi-mode)!: add back edit-command-line key binding as 'vv' (#9573)

BREAKING CHANGE: the key binding to open an editor to edit the command line has
been moved from being `v` (press v once) to being `vv` (press v twice). Now, the
action for `v` is the default `visual-mode`, as is in Vim.

Fixes #9573