Firefox specific execCommand no longer needed

[johanneswilm]

Hey,
Firefox stopped requiring disabling controls five years ago [1]. So you are now able to remove your last usages of document.execCommand for things like "enableInlineTableEditing" or "enableObjectResizing".

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1490641

I also see you have a few more places where you use execCommand. I would generally encourage you to find other alternatives as execCommand tends to break editors and most main editors have switched away from using it.