content: remove reference to new keyword

The slide about the `new` function was removed in 7f9714c.

Fixes golang/go#12891

Change-Id: I8d192a8261f5ab7eea8f0a677bd367503e023cc8
Reviewed-on: https://go-review.googlesource.com/15753
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/content/moretypes.article b/content/moretypes.article
index d2da592..1d8f9f8 100644
--- a/content/moretypes.article
+++ b/content/moretypes.article
@@ -185,7 +185,7 @@
 
 A map maps keys to values.
 
-Maps must be created with `make` (not `new`) before use; the `nil` map is empty and cannot be assigned to.
+Maps must be created with `make` before use; the `nil` map is empty and cannot be assigned to.
 
 .play moretypes/maps.go