[indexes][meta] typo

Author: tabatkins

indexes/Overview.bs

@@ -24,7 +24,7 @@ hidden somewhere in the haystack of CSS specs.
 
 There are some things missing,
 and there are several mistakes,
-either from use of legacy markup patterns that haven't been udpated yet,
+either from use of legacy markup patterns that haven't been updated yet,
 or the dfn-type-autodetector misfiring.
 These will be cleaned up over time.