doc: add history entries for JSON modules stabilization

PR-URL: nodejs#55855
Refs: nodejs#55333
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Jacob Smith <jacob@frende.me>

doc/api/esm.md

@@ -7,6 +7,9 @@
 <!-- YAML
 added: v8.5.0
 changes:
+  - version: v18.20.5
+    pr-url: https://github.com/nodejs/node/pull/55333
+    description: Import attributes are no longer experimental.
   - version: v18.20.0
     pr-url: https://github.com/nodejs/node/pull/50140
     description: Add experimental support for import attributes.
@@ -550,6 +553,13 @@ separate cache.
 
 ## JSON modules
 
+<!-- YAML
+changes:
+  - version: v18.20.5
+    pr-url: https://github.com/nodejs/node/pull/55333
+    description: JSON modules are no longer experimental.
+-->
+
 > Stability: 2 - Stable
 
 JSON files can be referenced by `import`: