handle edge case in searching: when we look for 'abba' in the text 'abbabba', it looks like we should have two matches, but to be consistent with other programs, we only have one match

shell/shell.sml

@@ -69,7 +69,7 @@ struct
         let
           val buffer = #buffer app
           val buffer = LineGap.goToEnd buffer
-          val searchString = "val "
+          val searchString = "abba"
           val searchList = SearchList.build (buffer, searchString)
           val buffer = LineGap.goToStart buffer
         in