tour: method call not correct

Fixes golang/tour#202.

Change-Id: Ibffa127f6bdbe9c2ce8d47f358d355795e214a2b
Reviewed-on: https://go-review.googlesource.com/40897
Reviewed-by: Chris Broadfoot <cbro@golang.org>
diff --git a/content/methods.article b/content/methods.article
index bb40024..7475369 100644
--- a/content/methods.article
+++ b/content/methods.article
@@ -82,8 +82,8 @@
 functions with a pointer argument must take a pointer:
 
 	var v Vertex
-	ScaleFunc(v)  // Compile error!
-	ScaleFunc(&v) // OK
+	ScaleFunc(v, 5)  // Compile error!
+	ScaleFunc(&v, 5) // OK
 
 while methods with pointer receivers take either a value or a pointer as the
 receiver when they are called:
@@ -291,7 +291,7 @@
 
 * Errors
 
-Go programs express error state with `error` values. 
+Go programs express error state with `error` values.
 
 The `error` type is a built-in interface similar to `fmt.Stringer`:
 
@@ -353,7 +353,7 @@
 populated and an error value. It returns an `io.EOF` error when the stream
 ends.
 
-The example code creates a 
+The example code creates a
 [[//golang.org/pkg/strings/#Reader][`strings.Reader`]]
 and consumes its output 8 bytes at a time.