_content/doc: fix link in go1.18.html

Change-Id: I595b5370c2a43fabeb3b24638dd00a402427363f
Reviewed-on: https://go-review.googlesource.com/c/website/+/393054
Reviewed-by: DO NOT USE <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Trust: David Chase <drchase@google.com>

_content/doc/go1.18.html

@@ -77,7 +77,7 @@ Do not send CLs removing the interior tags from such phrases.
     <a href="/ref/spec#Function_declarations">function</a> and
     <a href="/ref/spec#Type_declarations">type declarations</a>
     now accepts
-    <a href="/ref/spec#Type_parameters">type parameters</a>.
+    <a href="/ref/spec#Type_parameter_declarations">type parameters</a>.
   </li>
   <li>
     Parameterized functions and types can be instantiated by following them with a list of