doc/go1.19: add a release note for 'go list -json=SomeField'

For golang#29666.

Change-Id: I575375fb039e5809b0ed2ce985f6352a61142d63
Reviewed-on: https://go-review.googlesource.com/c/go/+/417595
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Bryan Mills <bcmills@google.com>

doc/go1.19.html

@@ -118,6 +118,15 @@ <h3 id="go-command">Go command</h3>
   and <code>GOGCCFLAGS</code> variables it reports.
 </p>
 
+<p><!-- https://go.dev/issue/29666 -->
+  <code>go</code> <code>list</code> <code>-json</code> now accepts a
+  comma-separated list of JSON fields to populate. If a list is specified,
+  the JSON output will include only those fields, and
+  <code>go</code> <code>list</code> may avoid work to compute fields that are
+  not included. In some cases, this may suppress errors that would otherwise
+  be reported.
+</p>
+
 <p><!-- CL 410821 -->
   The <code>go</code> command now caches information necessary to load some modules,
   which should result in a speed-up of some <code>go</code> <code>list</code> invocations.