remove mention of experimental status from release note

documentation/src/docs/asciidoc/release-notes/release-notes-5.12.0-M1.adoc

@@ -86,7 +86,7 @@ JUnit repository on GitHub.
   a test-scoped `ExtensionContext` in `Extension` methods called during test class
   instantiation. This behavior will become the default in future versions of JUnit.
 * `@TempDir` is now supported on test class constructors.
-* `@ParameterizedTest`s now support argument count validation as an experimental feature.
+* `@ParameterizedTest`s now support argument count validation.
   With the `junit.jupiter.params.argumentCountValidation=strict` configuration
   or the `@ParameterizedTest(argumentCountValidation = ArgumentCountValidationMode.STRICT)` attribute,
   any mismatch between the declared number of arguments and the number of arguments provided by the arguments source