Merge pull request #46929 from CaoShuFeng/extra_newline

Automatic merge from submit-queue (batch tested with PRs 46929, 47391, 47399, 47428, 47274)

Remove empty lines from log

Everything() returns a new line end with "\n", it's not necessary
to add another one.
**Release note**:

```
NONE
```

staging/src/k8s.io/apiserver/pkg/audit/format.go

@@ -60,7 +60,7 @@ func EventString(ev *auditinternal.Event) string {
 		ip = ev.SourceIPs[0]
 	}
 
-	return fmt.Sprintf("%s AUDIT: id=%q stage=%q ip=%q method=%q user=%q groups=%q as=%q asgroups=%q namespace=%q uri=%q response=\"%s\"\n",
+	return fmt.Sprintf("%s AUDIT: id=%q stage=%q ip=%q method=%q user=%q groups=%q as=%q asgroups=%q namespace=%q uri=%q response=\"%s\"",
 		ev.Timestamp.Format(time.RFC3339Nano), ev.AuditID, ev.Stage, ip, ev.Verb, username, groups, asuser, asgroups, namespace, ev.RequestURI, response)
 }
 

staging/src/k8s.io/apiserver/pkg/audit/metrics.go

@@ -72,7 +72,7 @@ func ObservePolicyLevel(level auditinternal.Level) {
 
 // HandlePluginError handles an error that occurred in an audit plugin. This method should only be
 // used if the error may have prevented the audit event from being properly recorded. The events are
-// modified.
+// logged to the debug log.
 func HandlePluginError(plugin string, err error, impacted ...*auditinternal.Event) {
 	// Count the error.
 	errorCounter.WithLabelValues(plugin).Add(float64(len(impacted)))

staging/src/k8s.io/apiserver/plugin/pkg/audit/log/backend.go

@@ -47,7 +47,7 @@ func (b *backend) ProcessEvents(events ...*auditinternal.Event) {
 
 func (b *backend) logEvent(ev *auditinternal.Event) {
 	line := audit.EventString(ev)
-	if _, err := fmt.Fprint(b.out, line); err != nil {
+	if _, err := fmt.Fprintln(b.out, line); err != nil {
 		audit.HandlePluginError("log", err, ev)
 	}
 }