Add link to use cases doc

Overview.bs

@@ -57,6 +57,10 @@ provided it behaves as if the underlying programming interfaces were in place.
 
 <em>This section is non-normative</em>
 
+Note: Based on this <a
+href="https://github.com/birtles/scroll-animations/blob/master/Use%20cases.md">curated
+list of use cases</a>.
+
 ## Scroll-triggered animations ## {#scroll-triggered-animations-usecases}
 
 ### Navigation bar shrinking effect ### {#navigation-bar-shrinking-effect}

Use cases.md

@@ -1,5 +1,3 @@
-Curated use cases:
-
 1. Scroll-triggered animations
 ---------------------------------
 

index.html

@@ -399,6 +399,8 @@ <h3 class="heading settled" data-level="1.1" id="other-specs"><span class="secno
 provided it behaves as if the underlying programming interfaces were in place.</p>
    <h2 class="heading settled" data-level="2" id="use-cases"><span class="secno">2. </span><span class="content">Use cases</span><a class="self-link" href="#use-cases"></a></h2>
    <p><em>This section is non-normative</em></p>
+   <p class="note" role="note">Note: Based on this <a href="https://github.com/birtles/scroll-animations/blob/master/Use%20cases.md">curated
+list of use cases</a>.</p>
    <h3 class="heading settled" data-level="2.1" id="scroll-triggered-animations-usecases"><span class="secno">2.1. </span><span class="content">Scroll-triggered animations</span><a class="self-link" href="#scroll-triggered-animations-usecases"></a></h3>
    <h4 class="heading settled" data-level="2.1.1" id="navigation-bar-shrinking-effect"><span class="secno">2.1.1. </span><span class="content">Navigation bar shrinking effect</span><a class="self-link" href="#navigation-bar-shrinking-effect"></a></h4>
    <p>It is common to trigger an animation to run when the scroll position