[css-shapes-2] Fix typo in link to css-shapes-1 (#12295)

Author: tidoust

css-shapes-2/Overview.bs

@@ -131,7 +131,7 @@ Supported Shapes</h3>
 The ''shape()'' Function</h4>
 
 	Add the final
-	<a href="https://https://drafts.csswg.org/css-shapes-1/#shape-function">level 1</a>
+	<a href="https://drafts.csswg.org/css-shapes-1/#shape-function">level 1</a>
 	section.
 
 <h2 id='referencing-svg-shapes'>