Update CHANGELOG for new block Imp test functions

Author: neilmayhew

eras/shelley/impl/CHANGELOG.md

@@ -40,6 +40,28 @@
 
 ### `testlib`
 
+* Add:
+  - `submitBlock_`
+  - `submitBlock`
+  - `submitFailingBlock`
+  - `submitFailingBlockM`
+  - `submitBlockNoFixup_`
+  - `submitBlockNoFixup`
+  - `submitFailingBlockNoFixup`
+  - `submitFailingBlockNoFixupM`
+  - `trySubmitBlock`
+  - `trySubmitBlockNoFixup`
+  - `withTxsInBlock_`
+  - `withTxsInBlock`
+  - `withTxsInFailingBlock`
+  - `withTxsInFailingBlockM`
+* Remove `tryRunImpBBODY`
+* Add `simulateThenRestore_`
+* Change the type of `simulateThenRestore`
+* Add `Eq` instances for:
+  - `AlonzoBbodyEvent`
+  - `ShelleyBbodyEvent`
+  - `ShelleyLedgersEvent`
 * Add `NFData` and `ToExpr` constraints and instances for:
   - `AlonzoBlockBody`
   - `AlonzoBbodyPredFailure`