Add release notes wrt #1470

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -498,3 +498,8 @@ Fawzi Essam (@iifawzi)
 
 Ilenia Salvadori (@isalvadori)
  * Requested #1421: Make `JsonReadContext` non-final
+  (2.19.0)
+
+Lars Hagen (@larshagencognite)
+ * Contributed #1470: Add method `copyCurrentStructureExact()` to `JsonGenerator`
+  (2.21.0)

release-notes/VERSION-2.x

@@ -16,7 +16,8 @@ a pure JSON library.
 
 2.21.0 (not yet released)
 
-No changes since 2.20
+#1470: Add method `copyCurrentStructureExact()` to `JsonGenerator`
+ (contributed by Lars H)
 
 2.20.0 (28-Aug-2025)