yanglint BUGFIX check of parent data node for oper

Checking that a parent data node exists in the datastore for the
nested-notification and action.
diff --git a/tools/lint/tests/data/modaction_ds.xml b/tools/lint/tests/data/modaction_ds.xml
new file mode 100644
index 0000000..a5a1727
--- /dev/null
+++ b/tools/lint/tests/data/modaction_ds.xml
@@ -0,0 +1,5 @@
+<con xmlns="urn:yanglint:modaction">
+  <ls>
+    <lfkey>kv</lfkey>
+  </ls>
+</con>