JS: Move Directive subclasses into Directive module

javascript/ql/src/Expressions/UnknownDirective.ql

@@ -12,7 +12,7 @@ import javascript
 
 from Directive d
 where
-  not d instanceof KnownDirective and
+  not d instanceof Directive::KnownDirective and
   // ignore ":" pseudo-directive sometimes seen in dual-use shell/node.js scripts
   not d.getExpr().getStringValue() = ":" and
   // but exclude attribute top-levels: `<a href="javascript:'some-attribute-string'">`