docs/microvm.rst: fix alignment in "Limitations"

Fix the alignment of the items in the "Limitations" section.

Signed-off-by: Sergio Lopez <slp@redhat.com>
Message-Id: <20191115161338.42864-2-slp@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/microvm.rst

@@ -33,9 +33,9 @@ Limitations
 
 Currently, microvm does *not* support the following features:
 
- - PCI-only devices.
- - Hotplug of any kind.
- - Live migration across QEMU versions.
+- PCI-only devices.
+- Hotplug of any kind.
+- Live migration across QEMU versions.
 
 
 Using the microvm machine type