path: change the output format of ExampleSplit function

At the moment the last output line of ExampleSplit- two empty strings- are being
trimmed from the output.  I have formatted the output of the function to avoid
whitespace trimming and show empty strings more clearly.

Fixes #23542

Change-Id: Ic2a4d98cfa06db1466c6c6d98099542df9e7c88b
Reviewed-on: https://go-review.googlesource.com/c/go/+/191397
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

src/path/example_test.go

@@ -102,11 +102,15 @@ func ExampleMatch() {
 }
 
 func ExampleSplit() {
-	fmt.Println(path.Split("static/myfile.css"))
-	fmt.Println(path.Split("myfile.css"))
-	fmt.Println(path.Split(""))
+	split := func(s string) {
+		dir, file := path.Split(s)
+		fmt.Printf("path.Split(%q) = dir: %q, file: %q\n", s, dir, file)
+	}
+	split("static/myfile.css")
+	split("myfile.css")
+	split("")
 	// Output:
-	// static/ myfile.css
-	//  myfile.css
-	//
+	// path.Split("static/myfile.css") = dir: "static/", file: "myfile.css"
+	// path.Split("myfile.css") = dir: "", file: "myfile.css"
+	// path.Split("") = dir: "", file: ""
 }