events: graduate capturerejections to supported

These have been around long enough to warrant graduation.

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/41267
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

doc/api/events.md

@@ -173,8 +173,6 @@ myEmitter.emit('error', new Error('whoops!'));
 
 ## Capture rejections of promises
 
-> Stability: 1 - captureRejections is experimental.
-
 Using `async` functions with event handlers is problematic, because it
 can lead to an unhandled rejection in case of a thrown exception:
 
@@ -741,10 +739,12 @@ emitter.emit('log');
 added:
  - v13.4.0
  - v12.16.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/41267
+    description: No longer experimental.
 -->
 
-> Stability: 1 - captureRejections is experimental.
-
 * `err` Error
 * `eventName` {string|symbol}
 * `...args` {any}
@@ -1028,10 +1028,12 @@ foo().then(() => console.log('done'));
 added:
  - v13.4.0
  - v12.16.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/41267
+    description: No longer experimental.
 -->
 
-> Stability: 1 - captureRejections is experimental.
-
 Value: {boolean}
 
 Change the default `captureRejections` option on all new `EventEmitter` objects.
@@ -1040,12 +1042,14 @@ Change the default `captureRejections` option on all new `EventEmitter` objects.
 
 <!-- YAML
 added:
- - v13.4.0
- - v12.16.0
+  - v13.4.0
+  - v12.16.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/41267
+    description: No longer experimental.
 -->
 
-> Stability: 1 - captureRejections is experimental.
-
 Value: `Symbol.for('nodejs.rejection')`
 
 See how to write a custom [rejection handler][rejection].