[css-borders-4] Typo (#12297)

Author: cdoublev

css-borders-4/Overview.bs

@@ -473,7 +473,7 @@ The 'corner-shape' Shorthand</h4>
 	<pre class=prod>
 		<dfn><<corner-shape-value>></dfn> = <l>''round''</l> | <l>''scoop''</l> | <l>''bevel''</l> | <l>''notch''</l> | <l>''<corner-shape-value>/square''</l> | <l>''squircle''</l> |
 		                       <<superellipse()>>
-		<dfn>super-ellipse()</dfn> = superellipse(<<number [-&infin;,&infin;]>> | infinity | -infinity)
+		<dfn>superellipse()</dfn> = superellipse(<<number [-&infin;,&infin;]>> | infinity | -infinity)
 	</pre>
 
 	<dl dfn-type="value" dfn-for="<corner-shape-value>, corner-shape">