Adding 'Insert Checklist' icon in Note Editor

[pachlava]

What

macOS version is the only not having 'Insert Checklist' icon.

Also, see comment here: p2XJRt-2J3-p2#comment-5169

I’d vote for removing the Format menu item once we move the icon to the top bar, since it only has that one thing in it and the name is a bit of a false promise (I would’ve expected to find bold and italics under Format for example).

Why

It's available on iOS, Electron and Android.

[mdrockwell]

Also requested here: 3811491-zen