moretypes: fixed minor typo

Updates golang/go#14040.

Fixes `structwhen` to become `struct when`.

Change-Id: I2cc4f9bded5d4ec4922d8daf49dbb6738210c096
Reviewed-on: https://go-review.googlesource.com/20028
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/content/moretypes.article b/content/moretypes.article
index 958d496..e314a2c 100644
--- a/content/moretypes.article
+++ b/content/moretypes.article
@@ -47,7 +47,7 @@
 
 Struct fields can be accessed through a struct pointer.
 
-To access the field `X` of a structwhen we have the struct pointer `p` we could
+To access the field `X` of a struct when we have the struct pointer `p` we could
 write `(*p).X`.
 However, that notation is cumbersome, so the language permits us instead to
 write just `p.X`, without the explicit dereference.