Update ref.html

doc/ref.html

@@ -184,7 +184,7 @@ class Main extends hxd.App {
 	The following blend mode values are available :</li>
 		<ul>
 			<li><code>Alpha</code> (default) : the drawable blends itself with the background using its alpha value. An opaque pixel will erase the background, a fully transparent one will be ignored.</li>
-			<li><code>None</code> : this disable the blending with the background. Alpha channel is ignored and the color is written as-it. This offers the best display performances for large backgrounds that have nothing showing being them</li>
+			<li><code>None</code> : this disable the blending with the background. Alpha channel is ignored and the color is written as-it. This offers the best display performances for large backgrounds that have nothing showing behind them</li>
 			<li><code>Add</code> : the drawable color will be added to the background, useful for creating explosions effects or particles for instance.</li>
 			<li><code>SoftAdd</code> : similar to Add but will prevent over saturation</li>
 			<li><code>Multiply</code> : the sprite color is multiplied by the background color</li>
@@ -396,4 +396,4 @@ class Main extends hxd.App {
 
 
 </body>
-</html>
+</html>