test: Require standard txs in regtest

doc/release-notes.md

@@ -103,6 +103,20 @@ Low-level Changes section below.
 Low-level changes
 =================
 
+RPC
+---
+
+
+Tests
+-----
+
+- The regression test chain, that can be enabled by the `-regtest` command line
+  flag, now requires transactions to not violate standard policy by default.
+  Making the default the same as for mainnet, makes it easier to test mainnet
+  behavior on regtest. Be reminded that the testnet still allows non-standard
+  txs by default and that the policy can be locally adjusted with the
+  `-acceptnonstdtxn` command line flag for both test chains.
+
 Configuration
 ------------