gopls/doc: update tests that fail on Kokoro to run at Go 1.21+

TestGenerated and TestLicenses both fail on Kokoro, for unknown reasons,
and only need to be run on one Go version.

Change-Id: I49950c7b6f34747ee94960f5cc0860cd348b391e
Reviewed-on: https://go-review.googlesource.com/c/tools/+/522235
gopls-CI: kokoro <noreply+kokoro@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

gopls/doc/generate_test.go

@@ -12,9 +12,9 @@ import (
 
 func TestGenerated(t *testing.T) {
 	testenv.NeedsGoPackages(t)
-	// This test fails on 1.18 Kokoro for unknown reasons; in any case, it
-	// suffices to run this test on any builder.
-	testenv.NeedsGo1Point(t, 19)
+	// This test fails on Kokoro, for unknown reasons, so must be run only on TryBots.
+	// In any case, it suffices to run this test on any builder.
+	testenv.NeedsGo1Point(t, 21)
 
 	testenv.NeedsLocalXTools(t)
 

gopls/internal/hooks/licenses_test.go

@@ -18,7 +18,7 @@ func TestLicenses(t *testing.T) {
 	// License text differs for older Go versions because staticcheck or gofumpt
 	// isn't supported for those versions, and this fails for unknown, unrelated
 	// reasons on Kokoro legacy CI.
-	testenv.NeedsGo1Point(t, 19)
+	testenv.NeedsGo1Point(t, 21)
 
 	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
 		t.Skip("generating licenses only works on Unixes")