[x/tour] content: say that a a pointer points to a 'value', not 'variable'

Fixes golang/go#16482

Change-Id: I8f30f817808eb65db3fa77ec810af978bf92ae24
Reviewed-on: https://go-review.googlesource.com/25163
Reviewed-by: Rob Pike <r@golang.org>
X-Tour-Commit: c9941e54e5b8e9618a8c951bc89798f85f6a7a71
diff --git a/tour/content/moretypes.article b/tour/content/moretypes.article
index bfae74f..64f7dc7 100644
--- a/tour/content/moretypes.article
+++ b/tour/content/moretypes.article
@@ -7,7 +7,7 @@
 * Pointers
 
 Go has pointers.
-A pointer holds the memory address of a variable.
+A pointer holds the memory address of a value.
 
 The type `*T` is a pointer to a `T` value. Its zero value is `nil`.