oauth2/google: fixed comment formatting and clarified naming

google/internal/externalaccount/clientauth.go

@@ -34,6 +34,4 @@ func (c *ClientAuthentication) InjectAuthentication(values url.Values, headers h
 		values.Set("client_id", c.ClientID)
 		values.Set("client_secret", c.ClientSecret)
 	}
-
-	return
 }

google/internal/externalaccount/err_test.go

@@ -2,7 +2,7 @@ package externalaccount
 
 import "testing"
 
-func TestError_Generator(t *testing.T) {
+func TestError(t *testing.T) {
 	e := Error{
 		"42",
 		"http:thisIsAPlaceholder",