Clarify that CheckSequenceLocksAtTip is a validation function

Author: MarcoFalke

src/validation.h

@@ -273,7 +273,7 @@ PackageMempoolAcceptResult ProcessNewPackage(CChainState& active_chainstate, CTx
                                                    const Package& txns, bool test_accept)
                                                    EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
-/* Transaction policy functions */
+/* Mempool validation helper functions */
 
 /**
  * Check if transaction will be final in the next block to be created.