fmt: add example for Print

Updates #27376

Change-Id: I2fa63b0d1981a419626072d985e6f3326f6013ff
Reviewed-on: https://go-review.googlesource.com/134035
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/fmt/example_test.go

@@ -49,6 +49,17 @@ func ExampleSprintf() {
 	// 15
 }
 
+func ExamplePrint() {
+	n, err := fmt.Print("there", "are", 99, "gophers", "\n")
+	if err != nil {
+		panic(err)
+	}
+	fmt.Print(n)
+	// Output:
+	// thereare99gophers
+	// 18
+}
+
 func ExamplePrintln() {
 	n, err := fmt.Println("there", "are", 99, "gophers")
 	if err != nil {