Fix doc for default print document content type

Since Kitkat the default was always 0 == document.

Change-Id: I9c6236073898f5e62ec80f95a21fd394802fe1dd
diff --git a/core/java/android/print/PrintDocumentInfo.java b/core/java/android/print/PrintDocumentInfo.java
index bec6f29..6143404 100644
--- a/core/java/android/print/PrintDocumentInfo.java
+++ b/core/java/android/print/PrintDocumentInfo.java
@@ -334,7 +334,7 @@
         /**
          * Sets the content type.
          * <p>
-         * <strong>Default: </strong> {@link #CONTENT_TYPE_UNKNOWN}
+         * <strong>Default: </strong> {@link #CONTENT_TYPE_DOCUMENT}
          * </p>
          *
          * @param type The content type.