_content/doc/tutorial: alias go to go1.18beta1 in generics.md

My memory and documentation I just looked up suggests the alias name
comes first, and the value second. Thanks to Hana for spotting this.

Change-Id: I981e49c5a9231c258606a8a7914ac9857923d903
Reviewed-on: https://go-review.googlesource.com/c/website/+/372055
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
diff --git a/_content/doc/tutorial/generics.md b/_content/doc/tutorial/generics.md
index d6fe749..be8bc8d 100644
--- a/_content/doc/tutorial/generics.md
+++ b/_content/doc/tutorial/generics.md
@@ -67,9 +67,10 @@
     *   By aliasing the beta name to another name, you can simplify the command:
 
         ```
-        $ alias go1.18beta1=go
+        $ alias go=go1.18beta1
         $ go version
-    ```
+        ```
+
 Commands in this tutorial will assume you have aliased the beta name.
 
 ## Create a folder for your code {#create_folder}