unified: Clarify description of derivedStoreReadStep

Author: asgerf

unified/ql/lib/codeql/unified/internal/StaticNameBinding.qll

@@ -264,13 +264,14 @@ module Track<TrackInputSig Input> {
 }
 
 /**
- * Holds if `node1 -> node2` is derived by combining a store and a read step.
+ * Holds if `node1 -> node2` is derived by combining a store and a read step, with zero or more value steps and inheritance steps in-between.
  */
 pragma[nomagic]
 private predicate derivedStoreReadStep(NameBindingNode node1, NameBindingNode node2) {
   exists(NamespaceNode namespace, string name |
-    node1 = namespace.getMember(name) and
-    readStep(namespace.ref(), name, node2)
+    node1 = namespace.getMember(name) and // getMember() combines a store step with subsequent inheritance steps
+    readStep(namespace.ref(), name, node2) and
+    node1 != node2
   )
 }