qapi: Fix enum doc comment checking

Enumeration type documentation comments are not checked, as
demonstrated by test doc-bad-enum-member.  This is because we neglect
to call self.doc.check() for enumeration types.  Messed up in
816a57cd6e "qapi: Fix detection of bogus member documentation".  Fix
it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191024110237.30963-10-armbru@redhat.com>

scripts/qapi/schema.py

@@ -229,6 +229,10 @@ class QAPISchemaEnumType(QAPISchemaType):
             for m in self.members:
                 self.doc.connect_member(m)
 
+    def check_doc(self):
+        if self.doc:
+            self.doc.check()
+
     def is_implicit(self):
         # See QAPISchema._make_implicit_enum_type() and ._def_predefineds()
         return self.name.endswith('Kind') or self.name == 'QType'