Rule move / subfolder: Added week number placeholder

FAQ.md

@@ -2592,6 +2592,7 @@ This will be more reliable than forwarding because forwarded messages might be c
 A *move* action can optionally create subfolders (since version 1.1966) to move messages to, for which you can use the following placeholders:
 
 ```
+$week$
 $month$
 $year$
 $domain$

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

@@ -623,9 +623,11 @@ public class EntityRule {
             Calendar calendar = Calendar.getInstance();
             String year = String.format(Locale.ROOT, "%04d", calendar.get(Calendar.YEAR));
             String month = String.format(Locale.ROOT, "%02d", calendar.get(Calendar.MONTH) + 1);
+            String week = String.format(Locale.ROOT, "%02d", calendar.get(Calendar.WEEK_OF_YEAR));
 
             create = create.replace("$year$", year);
             create = create.replace("$month$", month);
+            create = create.replace("$week$", week);
 
             String domain = null;
             if (message.from != null &&