[Bug] Sometimes the shorcuts does not apply

When you are editing text and select a word or block to apply **bold** or **italic** using shortcuts fails in some cases

Steps to reproduce:
1. Go to your text
2. select a block of text
3. do crtl + i or crtl + b
4. select the same bloc again
5. do crtl + i or crtl + b

Expected behavior:
bold & italic is applied in each time

Device, Browser, OS: chrome

Editor.js version: 2.19