Adds missing Status enum to dataprovider example (#11425)

documentation/datamodel/datamodel-providers.asciidoc

@@ -19,6 +19,25 @@ Regardless of how the items are loaded, the component is configured with one or
 In the following example, a [classname]#ComboBox# that lists status items is configured to use the [classname]#Status#.[methodname]#getCaption()# method to represent each status.
 There is also a [classname]#Grid#, which is configured with one column from the person's name and another showing the year of birth.
 
+[source, java]
+----
+public enum Status {
+  TODO, IN_PROGRESS, DONE;
+  
+  public String getCaption() {
+    switch (this) {
+    case TODO:
+      return "To do";
+    case IN_PROGRESS:
+      return "In Progress";
+    case DONE:
+      return "Done";
+    }
+    return "";
+  }
+}
+----
+
 [source, java]
 ----
 ComboBox<Status> comboBox = new ComboBox<>();