Gradle plugin bytecode enhancement configuration: updated the documentaiton and migration guide

Author: dreab8

documentation/src/main/asciidoc/introduction/Advanced.adoc

@@ -994,7 +994,9 @@ plugins {
     id "org.hibernate.orm" version "{fullVersion}"
 }
 
-hibernate { enhancement }
+hibernate {
+  enhancement {}
+}
 ----
 
 // [discrete]

migration-guide.adoc

@@ -92,6 +92,21 @@ Applications should instead use proper object-oriented encapsulation, exposing m
 
 Additionally, attempting to re-enhance a class with different options is no longer allowed and will result in a `FeatureMismatchException`.
 
+The Gradle plugin configuration has changed slightly. When using the default setup:
+
+```
+hibernate { enhancement }
+```
+
+it should be updated to:
+
+```
+hibernate {
+    enhancement {}
+}
+```
+
+in order to properly enable Bytecode Enhancement.
 
 [[session-getLobHelper]]
 === Session#getLobHelper