Add more specific "required" validation message (#60)

Fixes #59

Author: lex0r

components/Account.php

@@ -205,6 +205,9 @@ public function onSignin()
             $messages['login'] = $this->loginAttribute() == UserSettings::LOGIN_USERNAME
                 ? trans('winter.user::lang.account.invalid_username')
                 : trans('winter.user::lang.account.invalid_email');
+            $messages['login.required'] = $this->loginAttribute() == UserSettings::LOGIN_USERNAME
+                ? trans('winter.user::lang.account.required_username')
+                : trans('winter.user::lang.account.required_email');
 
             if (!array_key_exists('login', $data)) {
                 $data['login'] = post('username', post('email'));

lang/en/lang.php

@@ -180,6 +180,8 @@
         'invalid_current_pass' => 'The current password you entered was invalid.',
         'invalid_username' => 'The username you have entered is invalid.',
         'invalid_email' => 'The email address you have entered is invalid.',
+        'required_username' => 'The username field is required.',
+        'required_email' => 'The email address field is required.',
         'success_activation' => 'Successfully activated your account.',
         'success_deactivation' => 'Successfully deactivated your account. Sorry to see you go!',
         'success_saved' => 'Settings successfully saved!',