doc/faq: update generics entry to reflect accepted proposal

For #43651

Change-Id: Idb511f4c759d9a77de289938c19c2c1d4a542a17
Reviewed-on: https://go-review.googlesource.com/c/go/+/291990
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

doc/go_faq.html

@@ -446,8 +446,10 @@ <h3 id="Why_doesnt_Go_have_feature_X">Why does Go not have feature X?</h3>
 <h3 id="generics">
 Why does Go not have generic types?</h3>
 <p>
-Generics may well be added at some point.  We don't feel an urgency for
-them, although we understand some programmers do.
+A <a href="https://golang.org/issue/43651">language proposal
+implementing a form of generic types</a> has been accepted for
+inclusion in the language.
+If all goes well it will be available in the Go 1.18 release.
 </p>
 
 <p>