remove unintended 'not' in background shorthand definition

Author: fantasai

css3-background/Overview.src.html

@@ -1117,7 +1117,7 @@ <h3 id="the-background">The 'background' shorthand property</h3>
 
 <pre class=prod><dfn><var>&lt;bg-layer&gt;</var></dfn> = <var>&lt;bg-image&gt;</var> || <var>&lt;bg-position&gt;</var> || / <var>&lt;bg-size&gt;</var> || <var>&lt;repeat-style&gt;</var> || <var>&lt;attachment&gt;</var> || <var>&lt;bg-origin&gt;</var> </pre>
 
-<p>where ''<var>&lt;bg-position&gt;</var>'' must not occur before
+<p>where ''<var>&lt;bg-position&gt;</var>'' must occur before
 ''/ <var>&lt;bg-size&gt;</var>'' if both are present.
 
 <pre class=prod><dfn><var>&lt;final-bg-layer&gt;</var></dfn> = <var>&lt;bg-image&gt;</var> || <var>&lt;bg-position&gt;</var> || / <var>&lt;bg-size&gt;</var> || <var>&lt;repeat-style&gt;</var> || <var>&lt;attachment&gt;</var> || <var>&lt;bg-origin&gt;</var> || <var>&lt;'background-color'&gt;</var></pre>
@@ -1265,9 +1265,8 @@ <h3 id="special-backgrounds">The backgrounds of special elements</h3>
 value of 'background-image' on the root element is ''none'' and its
 'background-color' is ''transparent'', user agents must instead propagate
 the computed values of the background properties from that element's first
-HTML <code class="html">BODY</code>, respectively, XHTML <code
-class="html">body</code> child
-element. The used values of that <code class="html">BODY</code> element's
+HTML <code class="html">BODY</code> or XHTML <code class="html">body</code>
+child element. The used values of that <code class="html">BODY</code> element's
 background properties are their initial values, and the propagated values
 are treated as if they were specified on the root element.
 It is recommended that authors of HTML documents specify the canvas background