cmd/nm: use print-style not printf-style

Change-Id: Ic977026a99a825954117902051e59928de9ccbdb
Reviewed-on: https://go-review.googlesource.com/c/go/+/435947
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: xie cui <523516579@qq.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
diff --git a/src/cmd/nm/nm.go b/src/cmd/nm/nm.go
index 178eeb2..78fa600 100644
--- a/src/cmd/nm/nm.go
+++ b/src/cmd/nm/nm.go
@@ -29,7 +29,7 @@
 `
 
 func usage() {
-	fmt.Fprintf(os.Stderr, helpText)
+	fmt.Fprint(os.Stderr, helpText)
 	os.Exit(2)
 }