Improve wording for transactional rollback rule semantics

Closes gh-35346

Author: sbrannen

framework-docs/modules/ROOT/pages/data-access/transaction/declarative/rolling-back.adoc

@@ -86,11 +86,13 @@ rollback rules may be configured via the `rollbackFor`/`noRollbackFor` and
 `rollbackForClassName`/`noRollbackForClassName` attributes, which allow rules to be
 defined based on exception types or patterns, respectively.
 
-When a rollback rule is defined with an exception type, that type will be used to match
-against the type of a thrown exception and its super types, providing type safety and
-avoiding any unintentional matches that may occur when using a pattern. For example, a
-value of `jakarta.servlet.ServletException.class` will only match thrown exceptions of
-type `jakarta.servlet.ServletException` and its subclasses.
+When a rollback rule is defined with an exception type – for example, via `rollbackFor` –
+that type will be used to match against the type of a thrown exception. Specifically,
+given a configured exception type `C`, a thrown exception of type `T` will be considered
+a match against `C` if `T` is equal to `C` or a subclass of `C`. This provides type
+safety and avoids any unintentional matches that may occur when using a pattern. For
+example, a value of `jakarta.servlet.ServletException.class` will only match thrown
+exceptions of type `jakarta.servlet.ServletException` and its subclasses.
 
 When a rollback rule is defined with an exception pattern, the pattern can be a fully
 qualified class name or a substring of a fully qualified class name for an exception type

spring-tx/src/main/java/org/springframework/transaction/annotation/Transactional.java

@@ -56,9 +56,12 @@
  * {@link #rollbackForClassName}/{@link #noRollbackForClassName}, which allow
  * rules to be specified as types or patterns, respectively.
  *
- * <p>When a rollback rule is defined with an exception type, that type will be
- * used to match against the type of a thrown exception and its super types,
- * providing type safety and avoiding any unintentional matches that may occur
+ * <p>When a rollback rule is defined with an exception type &mdash; for example,
+ * via {@link #rollbackFor} &mdash; that type will be used to match against the
+ * type of a thrown exception. Specifically, given a configured exception type
+ * {@code C}, a thrown exception of type {@code T} will be considered a match
+ * against {@code C} if {@code T} is equal to {@code C} or a subclass of {@code C}.
+ * This provides type safety and avoids any unintentional matches that may occur
  * when using a pattern. For example, a value of
  * {@code jakarta.servlet.ServletException.class} will only match thrown exceptions
  * of type {@code jakarta.servlet.ServletException} and its subclasses.