Merge pull request #37785 from tanshanshan/fix-small

Automatic merge from submit-queue (batch tested with PRs 37692, 37785, 37647, 37941, 37856)

fix scheduler extender example

<!--  Thanks for sending a pull request!  Here are some tips for you:
1. If this is your first time, read our contributor guidelines https://github.com/kubernetes/kubernetes/blob/master/CONTRIBUTING.md and developer guide https://github.com/kubernetes/kubernetes/blob/master/docs/devel/development.md
2. If you want *faster* PR reviews, read how: https://github.com/kubernetes/kubernetes/blob/master/docs/devel/faster_reviews.md
3. Follow the instructions for writing a release note: https://github.com/kubernetes/kubernetes/blob/master/docs/devel/pull-requests.md#release-notes
-->

**What this PR does / why we need it**:

Fix scheduler extender example , refer to [kubernetes/plugin/pkg/scheduler/api/types.go](https://github.com/kubernetes/kubernetes/blob/master/plugin/pkg/scheduler/api/types.go)

Thanks!
**Special notes for your reviewer**:

**Release note**:
<!--  Steps to write your release note:
1. Use the release-note-* labels to set the release note state (if you have access) 
2. Enter your extended release note in the below block; leaving it blank means using the PR title as the release note. If no release note is required, just write `NONE`. 
-->
```release-note
```

scheduler-policy-config-with-extender.json

@@ -14,12 +14,14 @@
 	{"name" : "ServiceSpreadingPriority", "weight" : 1},
 	{"name" : "EqualPriority", "weight" : 1}
 	],
-"extender": {
-        "url": "http://127.0.0.1:12346/scheduler",
+"extenders":[ 
+	{
+        "urlPrefix": "http://127.0.0.1:12346/scheduler",
         "apiVersion": "v1beta1",
         "filterVerb": "filter",
         "prioritizeVerb": "prioritize",
         "weight": 5,
         "enableHttps": false
 	}
+    ]
 }