[cssom-view-1] Double word "attribute" (w3c#5960)

Author: nschonni

cssom-view-1/Overview.bs

@@ -536,14 +536,14 @@ scroll bar (if any), or zero if there is no <a>viewport</a>. <!--fingerprint-->
 The  <dfn attribute for=Window>innerHeight</dfn> attribute must return the <a>viewport</a> height including the size of a rendered
 scroll bar (if any), or zero if there is no <a>viewport</a>. <!--fingerprint-->
 
-The <dfn attribute for=Window>scrollX</dfn> attribute attribute must return the x-coordinate,
+The <dfn attribute for=Window>scrollX</dfn> attribute must return the x-coordinate,
 relative to the <a>initial containing block</a> origin,
 of the left of the <a>viewport</a>,
 or zero if there is no <a>viewport</a>. <!--fingerprint-->
 
 The <dfn attribute for=Window>pageXOffset</dfn> attribute must return the value returned by the {{scrollX}} attribute.
 
-The <dfn attribute for=Window>scrollY</dfn> attribute attribute must return the y-coordinate,
+The <dfn attribute for=Window>scrollY</dfn> attribute must return the y-coordinate,
 relative to the <a>initial containing block</a> origin,
 of the top of the <a>viewport</a>,
 or zero if there is no <a>viewport</a>. <!--fingerprint-->