doc/go1.20: add release notes for cmd/go changes

Updates #41696.
Updates #50332.
Updates #41583.

Change-Id: I99e96a2996f14da262570a5cb5273dcdce45df2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/449075
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>

Author: Bryan C. Mills

doc/go1.20.html

@@ -59,18 +59,10 @@ <h3 id="go-command">Go command</h3>
   TODO: <a href="https://go.dev/issue/45454">https://go.dev/issue/45454</a>: provide build tags for architecture environment variables
 </p>
 
-<p><!-- https://go.dev/issue/50332 -->
-  TODO: https://go.dev/issue/50332: add -C flag to change directory
-</p>
-
 <p><!-- CL 448357: cmd/go: print test2json start events -->
   TODO: CL 448357: cmd/go: print test2json start events
 </p>
 
-<p><!-- https://go.dev/issue/41583 -->
-  TODO: https://go.dev/issue/41583: add go test -skip to skip specific tests
-</p>
-
 <p><!-- CL 432535: cmd/go: don't install most GOROOT .a files in pkg -->
   The Go distribution no longer ships with pre-compiled <code>.a</code>
   files for most of the packages in <code>GOROOT</code>, now only including
@@ -94,6 +86,25 @@ <h3 id="go-command">Go command</h3>
   the <code>GOPATH</code> install targets to unexpectedly remain in effect.)
 </p>
 
+<p><!-- https://go.dev/issue/41696, CL 416094 -->
+  The <code>-i</code> flag is no longer accepted by
+  <code>go</code> <code>build</code> and <code>go</code> <code>test</code>.
+  The flag has been <a href="https://go.dev/issue/41696">deprecated since Go 1.16</a>.
+</p>
+
+<p><!-- https://go.dev/issue/50332 -->
+  The <code>go</code> subcommands now accept
+  <code>-C</code> <code>&lt;dir&gt;</code> to change directory to &lt;dir&gt;
+  before performing the command, which may be useful for scripts that need to
+  execute commands in multiple different modules.
+</p>
+
+<p><!-- https://go.dev/issue/41583 -->
+  The <code>go</code> <code>test</code> command now accepts
+  <code>-skip</code> <code>&lt;pattern&gt;</code> to skip tests or subtests
+  matching <code>&lt;pattern&gt;</code>.
+</p>
+
 <h4 id="go-version"><code>go</code> <code>version</code></h4>
 
 <p><!-- https://go.dev/issue/48187 -->