add missing qldoc

Author: erik-krogh

javascript/ql/lib/semmle/javascript/security/dataflow/ExceptionXssCustomizations.qll

@@ -7,6 +7,11 @@
 import javascript
 import semmle.javascript.security.dataflow.RemoteFlowSources
 
+/**
+ * Provides sources, sinks, and sanitizers for reasoning about
+ * cross-site scripting vulnerabilities where the taint-flow passes through a thrown
+ * exception.
+ */
 module ExceptionXss {
   private import Xss::Shared as Shared
 

javascript/ql/lib/semmle/javascript/security/dataflow/StoredXssCustomizations.qll

@@ -5,6 +5,11 @@
 
 import javascript
 
+/**
+ * Provides sources, sinks, and sanitizers for reasoning about
+ * cross-site scripting vulnerabilities where the taint-flow passes through a thrown
+ * exception.
+ */
 module StoredXss {
   private import Xss::Shared as Shared