doc/go1.22: document removal of 'go get' support in GOPATH mode

For #61422.
Updates #60915.

Change-Id: Ia8ca12c163a02223b26c5e4cd4c1b6093978aba4
Reviewed-on: https://go-review.googlesource.com/c/go/+/548875
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: Bryan C. Mills

doc/go1.22.html

@@ -83,14 +83,13 @@ <h3 id="go-command">Go command</h3>
   but not both.
 </p>
 
-<!-- CL 518775 -->
+<!-- CL 518775, https://go.dev/issue/60915 -->
 <p>
-  <!-- cmd/go: delete GOPATH-mode get -->
-</p>
-
-<!-- https://go.dev/issue/60915 -->
-<p>
-  <!-- preserve basic GOPATH mode indefinitely -->
+  <code>go</code> <code>get</code> is no longer supported outside of a module in the
+  legacy <code>GOPATH</code> mode (that is, with <code>GO111MODULE=off</code>).
+  Other build commands, such as <code>go</code> <code>build</code> and
+  <code>go</code> <code>test</code>, will continue to work indefinitely
+  for legacy <code>GOPATH</code> programs.
 </p>
 
 <!-- CL 518776 -->