_content/doc/tutorial: remove use of deprecated math/rand.Seed

Fixes golang/go#58958

Change-Id: I5ef84f2fd350e3048649cf281e8272e62b2fc052
Reviewed-on: https://go-review.googlesource.com/c/website/+/475275
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/_content/doc/tutorial/greetings-multiple-people.html b/_content/doc/tutorial/greetings-multiple-people.html
index cb04159..9de0083 100644
--- a/_content/doc/tutorial/greetings-multiple-people.html
+++ b/_content/doc/tutorial/greetings-multiple-people.html
@@ -73,11 +73,6 @@
     return messages, nil
 }</ins>
 
-// Init sets initial values for variables used in the function.
-func init() {
-    rand.Seed(time.Now().UnixNano())
-}
-
 // randomFormat returns one of a set of greeting messages. The returned
 // message is selected at random.
 func randomFormat() string {
diff --git a/_content/doc/tutorial/random-greeting.html b/_content/doc/tutorial/random-greeting.html
index 4e9a1ed..86e580e 100644
--- a/_content/doc/tutorial/random-greeting.html
+++ b/_content/doc/tutorial/random-greeting.html
@@ -51,12 +51,7 @@
     return message, nil
 }
 
-<ins>// init sets initial values for variables used in the function.
-func init() {
-    rand.Seed(time.Now().UnixNano())
-}
-
-// randomFormat returns one of a set of greeting messages. The returned
+<ins>// randomFormat returns one of a set of greeting messages. The returned
 // message is selected at random.
 func randomFormat() string {
     // A slice of message formats.