Add documetnation for shutdown_timeout config.toml setting
What does this MR do?
Adds documentation for new setting introduced in !3657 (merged)
Why was this MR needed?
Please read #29560 (closed) for details.
What's the best way to test this MR?
What are the relevant issue numbers?
Closes #29560 (closed)
Edited by Tomasz Maczukin