doc, policy: Clarify comment on STANDARD_SCRIPT_VERIFY_FLAGS

Author: ajtowns

src/policy/policy.h

@@ -91,7 +91,8 @@ static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
 /**
  * Standard script verification flags that standard transactions will comply
  * with. However we do not ban/disconnect nodes that forward txs violating
- * these rules, for better forwards and backwards compatability.
+ * the additional (non-mandatory) rules here, to improve forwards and
+ * backwards compatability.
  */
 static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
                                                              SCRIPT_VERIFY_DERSIG |