comments on spec and a few other things

Change-Id: I154e452946209a158a8b6fbfb7579801a8186879
diff --git a/doc/tutorial/basics/aliases.md b/doc/tutorial/basics/aliases.md
index def895e..481294c 100644
--- a/doc/tutorial/basics/aliases.md
+++ b/doc/tutorial/basics/aliases.md
@@ -8,13 +8,12 @@
 
 A typical use case is to provide access to a shadowed field.
 
-Alias are not members of a struct and thus are not part of the model and
-cannot be accessed.
-
+Alias are not members of a struct. They can be referred to, but they do not
+appear in the output.
 
 <!-- CUE editor -->
 ```
-A = a  // A is an alias to a
+A = a  // A is an alias for a
 a: {
     d: 3
 }