message: docs: remove prefixed animation related CSS properties
  Angular has stopped to support browser that requires these CSS properties.
  All supported browsers support standard CSS properties:
  * rule
  * animation
  PR Close
diff: height: .3em;
  width: 6em;
  margin:-60px 0 0 -60px;
  - -webkit-animation:spin 4s linear infinite;
  - -moz-animation:spin 4s linear infinite;
  animation:spin 4s linear infinite;
  }
  -@-moz-keyframes spin { 100% { -moz-transform: rotate(360deg); } }
  -@-webkit-keyframes spin { 100% { -webkit-transform: rotate(360deg); } }
  -@keyframes spin { 100% { -webkit-transform: rotate(360deg); transform:rotate(360deg); } }
  +@keyframes spin { 100% { transform:rotate(360deg); } }
  .spinner-hidden {
  display:none;
  