content/slices.article: fix a typo

Change-Id: Id0b88adc1cf99b09149b75768b4e12f8d974eba0
Reviewed-on: https://go-review.googlesource.com/129455
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/content/slices.article b/content/slices.article
index 015d56f..324e8e1 100644
--- a/content/slices.article
+++ b/content/slices.article
@@ -422,7 +422,7 @@
 
 .play -edit slices/prog120.go /START/,/END/
 
-Another new technique is in this example is that we initialize the slice by writing a composite literal,
+Another new technique in this example is that we initialize the slice by writing a composite literal,
 which consists of the type of the slice followed by its elements in braces:
 
 .code slices/prog120.go /slice := /