docs(animations): renamed animate-show-hide to sample-show-hide

This always throws me off - I think it helps to make it clear that the class name is arbitrary, and
what matters is the .ng-etc classes.

Closes angular#5848

Author: robwormald

docs/content/guide/animations.ngdoc

@@ -21,33 +21,33 @@ Below is a quick example of animations being enabled for `ngShow` and `ngHide`:
       <label>
         <input type="checkbox" ng-model="checked" style="float:left; margin-right:10px;"> Is Visible...
       </label>
-      <div class="check-element animate-show-hide" ng-show="checked" style="clear:both;">
+      <div class="check-element sample-show-hide" ng-show="checked" style="clear:both;">
         Visible...
       </div>
     </div>
   </file>
   <file name="animations.css">
-    .animate-show-hide {
+    .sample-show-hide {
       padding:10px;
       border:1px solid black;
       background:white;
     }
 
-    .animate-show-hide.ng-hide-add, .animate-show-hide.ng-hide-remove {
+    .sample-show-hide.ng-hide-add, .sample-show-hide.ng-hide-remove {
       -webkit-transition:all linear 0.5s;
       -moz-transition:all linear 0.5s;
       -o-transition:all linear 0.5s;
       transition:all linear 0.5s;
       display:block!important;
     }
 
-    .animate-show-hide.ng-hide-add.ng-hide-add-active,
-    .animate-show-hide.ng-hide-remove {
+    .sample-show-hide.ng-hide-add.ng-hide-add-active,
+    .sample-show-hide.ng-hide-remove {
       opacity:0;
     }
 
-    .animate-show-hide.ng-hide-add,
-    .animate-show-hide.ng-hide-remove.ng-hide-remove-active {
+    .sample-show-hide.ng-hide-add,
+    .sample-show-hide.ng-hide-remove.ng-hide-remove-active {
       opacity:1;
     }
   </file>