## New undo step on applying attribute ([#21](https://github.com/ckeditor/ckeditor5-typing/issues/21))

*Every attribute change should create a new undo step.*

**Check**:

1. Type few letters.
1. Press styling button (italic, bold, etc).
1. Type few more letters.
1. Press undo button.

**Expected**:
Only the letters typed in step 3 should be undone.

5. Press undo button.

**Expected**:
Letters typed in step 1 should be undone.
