docs: Drop remark on now unsupported version of QEMU

In formatdomaincaps.rst under section documenting hyperv features
there's a paragraph describing behaviour with QEMU older than
6.1.0. Well, as of v11.2.0-rc1~216 the minimum required version
is 6.2.0 rendering the paragraph needless. Drop it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

docs/formatdomaincaps.rst

@@ -871,10 +871,6 @@ are supported. The ``features`` enum corresponds to the ``<hyperv/>`` element
 (well, its children) as documented in `Hypervisor features
 <formatdomain.html#hypervisor-features>`__.
 
-Please note that depending on the QEMU version some capabilities might be
-missing even though QEMU does support them. This is because prior to QEMU-6.1.0
-not all features were reported by QEMU.
-
 Launch security
 ^^^^^^^^^^^^^^^