feat: Make `CommandMode` toggleable

[Justin Su]

Description of the problem or steps to reproduce

I have CommandMode bound to Ctrl+` (backtick) on macOS and would like CommandMode to be toggleable, a la Toggle Terminal shortcut in VS Code.

I tried binding it to CommandMode|Escape, thinking that CommandMode would fail if it was already active, but that doesn't seem to work.

But explicit is better, so maybe the best way is to introduce a CommandModeToggle action.

Specifications

Commit hash: 68d88b57
OS: macOS Sonoma 14.5
Terminal: Ghostty

[Mikko]

You can achieve this by adding a binding to the command mode, for example I have this in my ~/.config/micro/bindings.json:

{
  "Ctrl-e": "CommandMode",
  "command": {
    "Ctrl-e": "AbortCommand",
  }
}

[Justin Su]

Thanks, should've read the docs 🙃

Except that doesn't actually work in the case of Ctrl-`. In fact, I can't seem to bind any \u001b sequence to AbortCommand.