Add contact language hint to about dialog

css/style.css

@@ -423,6 +423,12 @@ button.btn {
     margin-right: -1em;
 }
 
+/* about dialog */
+#about-contact-language {
+    font-size: 0.9em;
+    margin: -6px 0 6px 20px;
+}
+
 /*
 * DataTables
 */

index.html

@@ -249,7 +249,11 @@
                             information see
                             <a href="https://brouter.de/" target="_blank">brouter.de</a>.
                         </p>
-                        <p><i data-i18n="about.contact">Contact:</i><br /></p>
+                        <p><i data-i18n="about.contact">Contact:</i></p>
+
+                        <div id="about-contact-language" data-i18n="about.contact-language">
+                            Preferred language is English, as we have both international contributors and users.
+                        </div>
 
                         <ul>
                             <li>

locales/en.json

@@ -5,6 +5,7 @@
     "bug-reports-front": "web client / frontend.",
     "chat": "Chat with users and developers",
     "contact": "Contact:",
+    "contact-language": "Preferred language is English, as we have both international contributors and users.",
     "data": "Data:",
     "data-description": "This is based on <a href=\"https://www.openstreetmap.org\" target=\"_blank\">OpenStreetMap</a>. It is usually updated daily, see dates of <a href=\"https://brouter.de/brouter/segments4/\" target=\"_blank\">data files</a>.",
     "description": "Online service of the BRouter routing engine. For the offline Android app and more information see <a href=\"https://brouter.de/\" target=\"_blank\">brouter.de</a>",