Ruby: enable for PolyReDos but document why it still doesnt work

Author: asgerf

ruby/ql/lib/codeql/ruby/security/regexp/PolynomialReDoSQuery.qll

@@ -18,6 +18,17 @@ private module PolynomialReDoSConfig implements DataFlow::ConfigSig {
   predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
 
   predicate isBarrier(DataFlow::Node node) { node instanceof Sanitizer }
+
+  predicate observeDiffInformedIncrementalMode() { any() }
+
+  Location getASelectedSinkLocation(DataFlow::Node sink) {
+    result = sink.(Sink).getHighlight().getLocation()
+  }
+
+  Location getASelectedSinkLocationApprox(DataFlow::Node sink) {
+    // TODO: Still fails tests due to RegExpTerms having incorrect locations when the regexp is parsed from a string arising from constant folding.
+    result = sink.(Sink).getRegExp().getRootTerm().getLocation()
+  }
 }
 
 /**