[css-backgrounds-4] Use <bg-position> to avoid clashing with more limited <position> #7376

Author: fantasai

css-backgrounds-4/Overview.bs

@@ -40,13 +40,13 @@ Background Positioning: the 'background-position' shorthand property</h3>
 
 	<pre class="propdef shorthand">
 		Name: background-position
-		Value: <<position>>#
+		Value: <<bg-position>>#
 	</pre>
 
 	See [[CSS3BG]] for definition.
 
 	<p>Where
-	<pre class=prod><dfn>&lt;position&gt;</dfn> = [
+	<pre class=prod><dfn>&lt;bg-position&gt;</dfn> = [
 	  [ left | center | right | top | bottom | start | end | <<length-percentage>> ]
 	|
 	  [ left | center | right | x-start | x-end | <<length-percentage>> ]