Update README-QUIC.md with server-side QUIC support information

Update README-QUIC.md with server-side QUIC support information

- Add information about OpenSSL 3.5 server-side QUIC support

- Include specific command instructions for running the QUIC server example

- Explicitly note that s_server does NOT support QUIC

- Fix documentation formatting (trailing spaces and blank lines around code blocks)

Signed-off-by: Samson S. Kolge <eglok1980@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/27230)