Long messages in chat no longer have hanging indention

What I expected to happen was...:
A long message in chat usually has hanging indention just like in 20w16a and previous snapshots and versions.

What actually happened was...:
The message no longer has hanging indention, and it can eventually become unpleasant if there is many of them.

How to reproduce:

1. Type a long message in chat.
   → You will notice that the long message is no longer indented.