Replace repeated border-right-color with border-left-color (typo)

https://www.w3.org/Bugs/Public/show_bug.cgi?id=27886

source

@@ -107444,7 +107444,7 @@ table {
   attribute, its value is expected to be parsed using the <span>rules for parsing a legacy colour
   value</span>, and if that does not return an error, the user agent is expected to treat the
   attribute as a <span data-x="presentational hints">presentational hint</span> setting the element's
-  'border-top-color', 'border-right-color', 'border-bottom-color', and 'border-right-color'
+  'border-top-color', 'border-right-color', 'border-bottom-color', and 'border-left-color'
   properties to the resulting colour.</p>
 
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