Usability issues with code blocks

[mejo-]

Describe the bug
Code blocks behave weird in several regards in latest Text versions (tested on latest Nextcloud 33).

To Reproduce
Steps to reproduce the behavior:

1. Create a second code block by typing "```"
2. Paste multi-line content straight away
3. See the first line has extra padding on the left

[The following was not reproducible on second try]

1. Create a code block by typing "```"
2. Write something, press
3. The cursor disappears
4. Copy multi-line text from outside the code block
5. Place the cursor in the code block (sometimes it jumps out again straight away)
6. Paste copied text
7. See it appearing at the border of the code block (very top or bottom)

Server details:

• Nextcloud version: 33.0.3

Client details:

• OS: Linux (Wayland)
• Browser: Firefox 150.0.3

Logs

Nextcloud log (data/nextcloud.log)

Insert your Nextcloud log here

Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...