Merge pull request #57754 from ncdc/fix-kube-proxy-config-docs-and-json-tags

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

kube-proxy: fix field name comments & json tags

**What this PR does / why we need it**: correct some minor issues in the comments and json tags for some of the fields in the kube-proxy config structs.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
The udpTimeoutMilliseconds field in the kube-proxy configuration file has been renamed to udpIdleTimeout. Action required: administrators need to update their files accordingly.
```

This was extracted from my currently unmerged f074b28fe9, as requested [here](https://github.com/kubernetes/kubernetes/pull/52198#pullrequestreview-85538637).

@kubernetes/sig-network-pr-reviews @luxas

cmd/kube-proxy/app/server_test.go

@@ -430,7 +430,7 @@ mode: "%s"
 oomScoreAdj: 17
 portRange: "2-7"
 resourceContainer: /foo
-udpTimeoutMilliseconds: 123ms
+udpIdleTimeout: 123ms
 `
 
 	testCases := []struct {