doc: improve quic documentation

Signed-off-by: James M Snell <jasnell@gmail.com>
Assisted-by: Opencode:Opus 4.6
PR-URL: #63157
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Tim Perry <pimterry@gmail.com>

Author: jasnell