KVM: Documentation: Update entry for KVM_X86_SET_MSR_FILTER

It should be an accident when rebase, since we've already have section
8.25 (which is KVM_CAP_S390_DIAG318).  Fix the number.
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201001012044.5151-2-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Documentation/virt/kvm/api.rst

@@ -6367,7 +6367,7 @@ accesses that would usually trigger a #GP by KVM into the guest will
 instead get bounced to user space through the KVM_EXIT_X86_RDMSR and
 KVM_EXIT_X86_WRMSR exit notifications.
 
-8.25 KVM_X86_SET_MSR_FILTER
+8.27 KVM_X86_SET_MSR_FILTER
 ---------------------------
 
 :Architectures: x86