[css-images-3][editorial] Fix markup error

Author: fantasai

css-images-3/Overview.bs

@@ -1035,7 +1035,7 @@ Coloring the Gradient Line</h4>
 			With premultiplied colors,
 			transitions to or from "transparent" always look nice:
 
-			<object data="images/gradient2.svg" width="200"height="100">(Image requires SVG)</object>
+			<object data="images/gradient2.svg" width="200" height="100">(Image requires SVG)</object>
 
 			On the other hand,
 			if a gradient were to incorrectly transition in non-premultiplied space,
@@ -1045,7 +1045,7 @@ Coloring the Gradient Line</h4>
 			as it loses opacity,
 			and similarly with the blue's transition:
 
-			<object data="images/gradient3.svg" width="200"height="100">(Image requires SVG)</object>
+			<object data="images/gradient3.svg" width="200" height="100">(Image requires SVG)</object>
 		</div>
 
 	</details>