note experimental feature [ci skip]

NEWS.md

@@ -22,10 +22,6 @@ New language features
 Language changes
 ----------------
 
-  * `x^n` for integer literals `n` (e.g. `x^3` or `x^-3`) is now
-    lowered to `x^Val{n}`, to enable compile-time specialization
-    for literal integer exponents ([#20530]).
-
   * "Inner constructor" syntax for parametric types is deprecated. For example,
     in this definition:
     ```
@@ -66,6 +62,10 @@ Language changes
   * The identifier `_` can be assigned, but accessing its value is deprecated,
     allowing this syntax to be used in the future for discarding values ([#9343], [#18251]).
 
+  * Experimental feature: `x^n` for integer literals `n` (e.g. `x^3`
+    or `x^-3`) is now lowered to `x^Val{n}`, to enable compile-time
+    specialization for literal integer exponents ([#20530]).
+
 Breaking changes
 ----------------