Add title to recurring event delete dialog.

Fixes b/5681424 On tablet, after deleting a recurring event the pop-up that shows up doesn't have a title

Change-Id: I19d50358bf2d1122a80898278b26118013b96901
diff --git a/res/values/strings.xml b/res/values/strings.xml
index b79ad9e..83dab0c 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -418,6 +418,10 @@
          user has asked to delete an event. The user still has a chance to cancel
          this operation. -->
     <string name="delete_this_event_title">Delete this event?</string>
+    <!-- This is a confirmation message in a popup dialog that appears when the
+         user has asked to delete an event that is recurring. The user still has a chance to cancel
+         this operation. -->
+    <string name="delete_recurring_event_title">Delete <xliff:g id="eventtitle">%s</xliff:g>?</string>
     <!-- This is the title of a popup dialog that asks for confirmation before
          changing the response to an invitation. -->
     <string name="change_response_title">Change response</string>