Added more translations for Wait Spinners.

Thanks to xet7 !

i18n/en.i18n.json

@@ -1045,6 +1045,7 @@
   "Cube": "Cube Wait Spinner",
   "Cube-Grid": "Cube-Grid Wait Spinner",
   "Dot": "Dot Wait Spinner",
+  "Double-Bounce": "Double Bounce Wait Spinner",
   "Rotateplane": "Rotateplane Wait Spinner",
   "Scaleout": "Scaleout Wait Spinner",
   "Wave": "Wave Wait Spinner"