release 3.9.0 process: reduce warnings (#279)

* fix(riseupvpn): address gofmt warning

Thanks to https://goreportcard.com/report/github.com/ooni/probe-cli.

* fix(utils.go): correct the docu-comment

Thanks to https://goreportcard.com/report/github.com/ooni/probe-cli

* fix: improve spelling

Thanks to https://goreportcard.com/report/github.com/ooni/probe-cli

* fix(modelx_test.go): avoid inefassign warning

Thanks to https://goreportcard.com/report/github.com/ooni/probe-cli

* fix: reduce number of ineffective assignments

Thanks to https://goreportcard.com/report/github.com/ooni/probe-cli

internal/engine/legacy/netx/dialer_test.go

@@ -101,6 +101,9 @@ func TestDialerSetCABundleWAI(t *testing.T) {
 func TestDialerForceSpecificSNI(t *testing.T) {
 	dialer := netx.NewDialer()
 	err := dialer.ForceSpecificSNI("www.facebook.com")
+	if err != nil {
+		t.Fatal(err)
+	}
 	conn, err := dialer.DialTLS("tcp", "www.google.com:443")
 	if err == nil {
 		t.Fatal("expected an error here")

internal/engine/legacy/netx/modelx/modelx_test.go

@@ -56,7 +56,7 @@ func TestMeasurementRootWithMeasurementRootPanic(t *testing.T) {
 		}
 	}()
 	ctx := context.Background()
-	ctx = WithMeasurementRoot(ctx, nil)
+	_ = WithMeasurementRoot(ctx, nil)
 }
 
 func TestErrWrapperPublicAPI(t *testing.T) {