Fix typo in directoryBrowse attribute

Author: jzabroski

csharp/ql/src/Security Features/CWE-548/Web.config.bad

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <configuration>
   <system.webServer>
-    <directoryBrowse enable="true"/>
+    <directoryBrowse enabled="true"/>
    ...
   </system.web>
-</configuration>
+</configuration>