Tweak bottom padding for the "..." popup hint

Follow up to I45bd6edf

bug: 5255103

Change-Id: I6d5368dadbaf6c7dffadd783d8a8756fea9dbff7
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index e964889..3d6428d 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -63,6 +63,8 @@
         <attr name="keyLabelHorizontalPadding" format="dimension" />
         <!-- Top and right padding of hint letter to the edge of the key.-->
         <attr name="keyHintLetterPadding" format="dimension" />
+        <!-- Bottom padding of popup hint letter "..." to the edge of the key.-->
+        <attr name="keyPopupHintLetterPadding" format="dimension" />
         <!-- Top and right padding of upper case letter to the edge of the key.-->
         <attr name="keyUppercaseLetterPadding" format="dimension" />