KVM: x86/MMU: properly format KVM_CAP_VM_DISABLE_NX_HUGE_PAGES capability table

There is unexpected warning on KVM_CAP_VM_DISABLE_NX_HUGE_PAGES capability
table, which cause the table to be rendered as paragraph text instead.

The warning is due to missing colon at capability name and returns keyword,
as well as improper alignment on multi-line returns field.

Fix the warning by adding missing colons and aligning the field.

Link: https://lore.kernel.org/lkml/20220627181937.3be67263@canb.auug.org.au/
Fixes: 084cc29f ("KVM: x86/MMU: Allow NX huge pages to be disabled on a per-vm basis")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Matlack <dmatlack@google.com>
Cc: Ben Gardon <bgardon@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-next@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Message-Id: <20220627095151.19339-3-bagasdotme@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Documentation/virt/kvm/api.rst

@@ -8264,13 +8264,13 @@ available and supports the `KVM_PV_DUMP_CPU` subcommand.
 8.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES
 -------------------------------------
 
-:Capability KVM_CAP_VM_DISABLE_NX_HUGE_PAGES
+:Capability: KVM_CAP_VM_DISABLE_NX_HUGE_PAGES
 :Architectures: x86
 :Type: vm
 :Parameters: arg[0] must be 0.
-:Returns 0 on success, -EPERM if the userspace process does not
-	 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been
-	 created.
+:Returns: 0 on success, -EPERM if the userspace process does not
+          have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been
+          created.
 
 This capability disables the NX huge pages mitigation for iTLB MULTIHIT.