Added send failed retry hint

app/src/main/java/eu/faircode/email/ServiceSend.java

@@ -245,8 +245,13 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             builder.setContentText(Log.formatThrowable(ex, false))
                     .setStyle(new NotificationCompat.BigTextStyle()
                             .bigText(Log.formatThrowable(ex, "\n", false)));
-        } else
+        } else {
-            builder.setContentText(getString(R.string.title_notification_sending_left, tries_left));
+            String msg = getString(R.string.title_notification_sending_left, tries_left);
+            builder.setContentText(msg)
+                    .setStyle(new NotificationCompat.BigTextStyle()
+                            .bigText(msg + "\n" + getString(R.string.title_notification_sending_retry)));
+        }
+
         return builder;
     }
 

app/src/main/res/values/strings.xml

@@ -107,6 +107,7 @@
     <string name="title_notification_failed">\'%1$s\' failed</string>
     <string name="title_notification_alert">\'%1$s\' server alert</string>
     <string name="title_notification_sending_left">Attempts left: %1$d</string>
+    <string name="title_notification_sending_retry">Sending will be retried on internet connection changes or pulling down on the outbox</string>
     <string name="title_notification_sending_failed">Sending to %1$s failed</string>
 
     <string name="title_notification_redacted">Redacted: biometric or PIN authentication enabled</string>