KVM: Delete extra block of "};" in the KVM API documentation

Delete an extra block of code/documentation that snuck in when KVM's
documentation was converted to ReST format.

Fixes: 106ee47d ("docs: kvm: Convert api.txt to ReST format")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221207003637.2041211-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>