docs/about/emulation: Fix broken link

docs/about/emulation: Fix broken link

semihosting link to risc-v changed

Signed-off-by: Santiago Monserrat Campanello <santimonserr@gmail.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2717
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250305102632.91376-1-santimonserr@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
(cherry picked from commit 672cb29d1e811180bf1aeefbcb0936ecd5bd3853)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>