fix doc & example transition opacity from .99 to 1

docs/docs/09-addons.md

@@ -67,15 +67,15 @@ You can use these classes to trigger a CSS animation or transition. For example,
 }
 
 .example-enter.example-enter-active {
-  opacity: 0.99;
+  opacity: 1;
 }
 ```
 
 You'll notice that when you try to remove an item `ReactTransitionGroup` keeps it in the DOM. If you're using an unminified build of React you'll see a warning that React was expecting an animation or transition to occur. That's because `ReactTransitionGroup` keeps your DOM elements on the page until the animation completes. Try adding this CSS:
 
 ```css
 .example-leave {
-  opacity: 0.99;
+  opacity: 1;
   transition: opacity .5s ease-in;
 }
 

examples/transitions/transition.css

@@ -20,7 +20,7 @@
 .example-enter.example-enter-active,
 .example-leave {
   margin-left: 0;
-  opacity: 0.99;
+  opacity: 1;
 }
 
 .animateExample {