bugfix:add cases.NoLower option (#7052)

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**What this PR does / why we need it**:
see #7048 
if we don't apply cases.NoLower, it will upper first alphabet lower the
others
```go
package main

import (
	"fmt"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
	"strings"
)

func main() {
	source := "testAPI"
	fmt.Println(cases.Title(language.Und).String(source)) // out: Testapi
	fmt.Println(cases.Title(language.Und, cases.NoLower).String(source)) // out: TestAPI
	fmt.Println(strings.Title(source)) // out: TestAPI
}
```
**Which issue(s) this PR fixes**:


**Special notes for your reviewer**:

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**Checklist**
- [ ] Documentation added
- [ ] Tests updated
- [ ] Is this an important fix or new feature? Add an entry in the
`CHANGELOG.md`.
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`

Signed-off-by: wujw39640 <[email protected]>
Signed-off-by: wujunwei <[email protected]>
Co-authored-by: wujw39640 <[email protected]>

pkg/util/cfg/flag.go

@@ -94,7 +94,7 @@ func categorizedUsage(fs *flag.FlagSet) func() {
 			if name == "" {
 				continue
 			}
-			fmt.Fprintf(fs.Output(), " %s:\n", cases.Title(language.Und).String(name))
+			fmt.Fprintf(fs.Output(), " %s:\n", cases.Title(language.Und, cases.NoLower).String(name))
 			for _, u := range categories[name] {
 				fmt.Fprintln(fs.Output(), u)
 			}

pkg/util/cfg/flag_test.go

@@ -1,6 +1,7 @@
 package cfg
 
 import (
+	"bytes"
 	"flag"
 	"testing"
 	"time"
@@ -56,3 +57,22 @@ func TestFlags(t *testing.T) {
 		},
 	}, data)
 }
+
+// TestCategorizedUsage checks that the name of every flag can be "Titled" correctly
+func TestCategorizedUsage(t *testing.T) {
+	output := &bytes.Buffer{}
+	fs := flag.NewFlagSet(t.Name(), flag.PanicOnError)
+	fs.SetOutput(output)
+	// "TestAPI" expected
+	fs.String("testAPI.one", "", "")
+	fs.String("testAPI.two", "", "")
+	// "TESTapi" expected
+	fs.String("tESTapi.one", "", "")
+	fs.String("tESTapi.two", "", "")
+	// "TestAPI" expected
+	fs.String("TestAPI.one", "", "")
+	fs.String("TestAPI.two", "", "")
+	categorizedUsage(fs)()
+	expected := "Usage of TestCategorizedUsage:\n\n TestAPI:\n   -TestAPI.one string:\n      \n   -TestAPI.two string:\n      \n\n TESTapi:\n   -tESTapi.one string:\n      \n   -tESTapi.two string:\n      \n\n TestAPI:\n   -testAPI.one string:\n      \n   -testAPI.two string:\n      \n\n"
+	assert.Equal(t, expected, output.String())
+}