doc/go1.11: add time package changes to release notes

Change-Id: I6f8d9cc8997128d0076a3a3e82fe5155d53db40d
Reviewed-on: https://go-review.googlesource.com/124659Reviewed-by: Rob Pike <r@golang.org>

doc/go1.11.html

@@ -728,7 +728,10 @@ func f(v interface{}) {
 <dl id="time"><dt><a href="/pkg/time/">time</a></dt>
   <dd>
     <p><!-- CL 98157 -->
-      TODO: <a href="https://golang.org/cl/98157">https://golang.org/cl/98157</a>: add support for parsing timezones denoted by sign and offset
+	  Parsing of timezones denoted by sign and offset is now
+	  supported. In previous versions, numeric timezone names
+	  (such as <code>+03</code>) were not considered valid, and only
+	  three-letter abbreviations (such as <code>MST</code>) were accepted
+	  when expecting a timezone name.
     </p>
-
 </dl><!-- time -->