strings: add examples for specialCase

Change-Id: Ifa0384722dd879af7f5edb7b7aaac5ede3cff46d
Reviewed-on: https://go-review.googlesource.com/74690
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/strings/example_test.go

@@ -249,6 +249,12 @@ func ExampleToTitle() {
 	// ХЛЕБ
 }
 
+func ExampleToTitleSpecial() {
+	fmt.Println(strings.ToTitleSpecial(unicode.TurkishCase, "dünyanın ilk borsa yapısı Aizonai kabul edilir"))
+	// Output:
+	// DÜNYANIN İLK BORSA YAPISI AİZONAİ KABUL EDİLİR
+}
+
 func ExampleMap() {
 	rot13 := func(r rune) rune {
 		switch {
@@ -274,11 +280,21 @@ func ExampleToUpper() {
 	// Output: GOPHER
 }
 
+func ExampleToUpperSpecial() {
+	fmt.Println(strings.ToUpperSpecial(unicode.TurkishCase, "örnek iş"))
+	// Output: ÖRNEK İŞ
+}
+
 func ExampleToLower() {
 	fmt.Println(strings.ToLower("Gopher"))
 	// Output: gopher
 }
 
+func ExampleToLowerSpecial() {
+	fmt.Println(strings.ToLowerSpecial(unicode.TurkishCase, "Önnek İş"))
+	// Output: önnek iş
+}
+
 func ExampleTrim() {
 	fmt.Print(strings.Trim("¡¡¡Hello, Gophers!!!", "!¡"))
 	// Output: Hello, Gophers