Warning about locale. [skip ci]

resources/lang/en_US/firefly.php

@@ -103,6 +103,7 @@ return [
     'all_periods'                                => 'All periods',
     'current_period'                             => 'Current period',
     'show_the_current_period_and_overview'       => 'Show the current period and overview',
+    'pref_languages_locale'                      => 'For a language other than English to work properly, your operating system must be equipped with the correct locale-information. If these are not present, currency data, dates and amounts may be formatted wrong.',
 
     // repeat frequencies:
     'repeat_freq_yearly'                         => 'yearly',

resources/views/preferences/index.twig

@@ -45,6 +45,11 @@
                                                 </div>
                                             {% endif %}
                                         {% endfor %}
+
+                                        <p class="text-info">
+                                            <br />
+                                            {{ 'pref_languages_locale'|_ }}
+                                        </p>
                                     </div>
 
                                     <!-- fiscal year -->