_content/doc/install.html: eliminate redundant link

I have just remove this paragraph:
"Don't see your operating system here? Try one of the other downloads." Some newbies are confuse by this so better remove it because it leads to the same page to  "Download (1.20.6)".

Fixes golang/go#61311

Change-Id: I9402dad754b9945b0c0dcc284eb6e8cdd229f999
GitHub-Last-Rev: 5b2e2a6b95b6c771d9fda13d6c49192e7a177b5c
GitHub-Pull-Request: golang/website#231
Reviewed-on: https://go-review.googlesource.com/c/website/+/509115
TryBot-Bypass: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/_content/doc/install.html b/_content/doc/install.html
index 8f93e53..57cc2fc 100644
--- a/_content/doc/install.html
+++ b/_content/doc/install.html
@@ -26,10 +26,6 @@
     </span>
   </a>
 </p>
-<p>
-  Don't see your operating system here? Try one of the
-  <a href="/dl/">other downloads</a>.
-</p>
 
 <h2 id="install">Go installation</h2>
 <p>