doc: upgrade stability status of report API

The property `process.report.reportOnFatalError`
was deemed experimental, as it was not honored
under certain scenarios (for example out of memory
conditions). The report configuration were previously
stored on the `environment` structure which was not
available on these types of fatal error cases.

The referenced PR has addressed this case (sometime
back), and the property is working as intended.

Refs: #32207
PR-URL: #35654
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Beth Griggs <bgriggs@redhat.com>

doc/api/process.md

@@ -1899,10 +1899,12 @@ Additional documentation is available in the [report documentation][].
 ### `process.report.reportOnFatalError`
 <!-- YAML
 added: v11.12.0
+changes:
+  - version:
+     - REPLACEME
+    description: This API is no longer experimental.
 -->
 
-> Stability: 1 - Experimental
-
 * {boolean}
 
 If `true`, a diagnostic report is generated on fatal errors, such as out of