update comment

Author: bishabosha

compiler/src/dotty/tools/dotc/core/TypeComparer.scala

@@ -2404,7 +2404,8 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
    *  1. Single inheritance of classes
    *  2. Final classes cannot be extended
    *  3. ConstantTypes with distinct values are non intersecting
-   *  4. There is no value of type Nothing
+   *  4. TermRefs with distinct values are non intersecting
+   *  5. There is no value of type Nothing
    *
    *  Note on soundness: the correctness of match types relies on on the
    *  property that in all possible contexts, the same match type expression