change 'use ase' to 'use case' (w3c#43)

Author: martine-dowden

Overview.bs

@@ -119,12 +119,12 @@ alt="Use case: A navigation highlight effect.">
 </figure>
 
 Advisement: The proposal does not yet define CSS markup or programming
-            interfaces to express this use ase.
+            interfaces to express this use case.
 
 ## Scroll-triggered style changes ## {#scroll-triggered-style-changes-usecase}
 
 Advisement: The proposal does not yet define CSS markup or programming
-            interfaces to express this use ase.
+            interfaces to express this use case.
 
 
 ## Scroll-linked animations ## {#scroll-linked-animations-usecase}

index.html

@@ -423,10 +423,10 @@ <h4 class="heading settled" data-level="2.1.2" id="navigation-highlight-effect">
   out. </figcaption>
    </figure>
    <p><strong class="advisement"> The proposal does not yet define CSS markup or programming
-            interfaces to express this use ase.</strong></p>
+            interfaces to express this use case.</strong></p>
    <h3 class="heading settled" data-level="2.2" id="scroll-triggered-style-changes-usecase"><span class="secno">2.2. </span><span class="content">Scroll-triggered style changes</span><a class="self-link" href="#scroll-triggered-style-changes-usecase"></a></h3>
    <p><strong class="advisement"> The proposal does not yet define CSS markup or programming
-            interfaces to express this use ase.</strong></p>
+            interfaces to express this use case.</strong></p>
    <h3 class="heading settled" data-level="2.3" id="scroll-linked-animations-usecase"><span class="secno">2.3. </span><span class="content">Scroll-linked animations</span><a class="self-link" href="#scroll-linked-animations-usecase"></a></h3>
    <h4 class="heading settled" data-level="2.3.1" id="scrollable-animation-usecase"><span class="secno">2.3.1. </span><span class="content">Scrollable picture-story show</span><a class="self-link" href="#scrollable-animation-usecase"></a></h4>
    <p>Another pattern is an animation that tells a story where the user