What it does

Fixes #13019

Firstly this fixes that output rendering is updated correctly when ouptut items changed.
Secondly this adds vscodes feature which concatinates stdOut and stdErr output items together.
The compression vscode is doing there is not implemented though.

How to test

create a notebook with a code cell like the following

import time
print('1')

time.sleep(1)

print('2')

time.sleep(1)

print('3')

execute the cell and see how all outputs appear one after the other

Follow-ups

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines