add ref to dynamic-range and fix video-prefixed-properties

Author: vi-dot-cpp

mediaqueries-4/Overview.bs

@@ -1733,7 +1733,7 @@ max brightness or low brightness as it relates to displays. As such, the
 determination for '@media/dynamic-range' and '@media/video-dynamic-range' will
 be defined by the user agent.
 
-<h3 id="video-prefixed-properties">Video Prefixed Feature</h3>
+<h3 id="video-prefixed-features">Video Prefixed Features</h3>
 
     Some user agents, including many TVs, render video and graphics in two
 	separate "planes" (bi-plane) with distinct screen characteristics. A set of
@@ -1781,7 +1781,7 @@ Video Dynamic Range: the 'video-dynamic-range' feature</h3>
 color depth, and contrast ratio that are supported by the UA and output device's
 video plane.
 
-Supported values are the same as dynamic-range.
+Supported values are the same as <a href="#dynamic-range">dynamic-range</a>.
 
 <h3 id="video-width">
 Video-Width: the '@media/video-width' feature</h3>