Add note about chase car visibility time

Author: Mark Jessop

index.html

@@ -295,7 +295,7 @@ <h2><i class="icon-car rfloat"></i>Chase Mode</h2>
                 <span class="r"><input type="text" id="cc_callsign" style="width: 140px;"/></span>
             </div>
             <div class="row">
-                <span><b>Notice: If you enable this, your location will be uploaded to SondeHub; making it publicly visible on the map.</b></span>
+                <span><b>Notice: If you enable this, your location will be uploaded to SondeHub; making it publicly visible on the map for up to 12 hours.</b></span>
             </div>
             <hr>
             <div class="row">