unicode: use IsSpace not IsUpper in IsSpace example test

Change-Id: Ie3017e5507f57cbb2ae9c8b737b378cef91fefeb
Reviewed-on: https://go-review.googlesource.com/c/go/+/354509
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/src/unicode/example_test.go b/src/unicode/example_test.go
index 416ad1f..d3a47ac 100644
--- a/src/unicode/example_test.go
+++ b/src/unicode/example_test.go
@@ -247,7 +247,7 @@
 	fmt.Printf("%t\n", unicode.IsSpace(' '))
 	fmt.Printf("%t\n", unicode.IsSpace('\n'))
 	fmt.Printf("%t\n", unicode.IsSpace('\t'))
-	fmt.Printf("%t\n", unicode.IsUpper('a'))
+	fmt.Printf("%t\n", unicode.IsSpace('a'))
 	// Output:
 	// true
 	// true