virt-xml-validate: add page (#9467)

pages/linux/virt-xml-validate.md

@@ -0,0 +1,13 @@
+# virt-xml-validate
+
+> Validate `libvirt` XML files against a schema.
+> If a schema is not specified, the schema is determined by the root element in the XML file.
+> More information: <https://libvirt.org/manpages/virt-xml-validate.html>.
+
+- Validate an XML file against a specific schema:
+
+`virt-xml-validate {{path/to/file.xml}} {{schema}}`
+
+- Validate the domain XML against the domain schema:
+
+`virt-xml-validate {{path/to/domain.xml}} domain`