Nested <code> elements

[ii888ii]

Steps to reproduce:

1. Type "A B C D E X a b c d e" in a paragraph.
2. Select "X" and click on InlineCode button (with "<>" icon)
3. Select "E X a" and click on InlineCode button
4. Select "D E X a b" and click on InlineCode button

And so on...

Expected behavior:

One <code> element instead of nested <code> elements

Screenshots:

Device, Browser, OS: Firefox and Chrome on Windows

Editor.js version: 2.30.7

[neSpecc]

It could be resolved by using pixels instead "ems" in styles