JS: Add deprecation qldoc to Configuration classes

Author: asgerf

javascript/ql/lib/semmle/javascript/dataflow/Configuration.qll

@@ -76,6 +76,11 @@ private import semmle.javascript.internal.CachedStages
 private import AdditionalFlowSteps
 
 /**
+ * DEPRECATED.
+ * Subclasses of this class should be replaced by a module implementing the new `ConfigSig` or `StateConfigSig` interface.
+ * See the [migration guide](https://codeql.github.com/docs/codeql-language-guides/migrating-javascript-dataflow-queries) for more details.
+ *
+ * #### Legacy documentation
  * A data flow tracking configuration for finding inter-procedural paths from
  * sources to sinks.
  *

javascript/ql/lib/semmle/javascript/dataflow/TaintTracking.qll

@@ -27,6 +27,13 @@ module TaintTracking {
   import AdditionalTaintSteps
 
   /**
+   * DEPRECATED.
+   * Subclasses of this class should be replaced by a module implementing the new `ConfigSig` or `StateConfigSig` interface.
+   * See the [migration guide](https://codeql.github.com/docs/codeql-language-guides/migrating-javascript-dataflow-queries) for more details.
+   *
+   * When migrating a `TaintTracking::Configuration` to `DataFlow::ConfigSig`, use `TaintTracking::Global<...>` instead of `DataFlow::Global<...>`.
+   *
+   * #### Legacy documentation
    * A data flow tracking configuration that considers taint propagation through
    * objects, arrays, promises and strings in addition to standard data flow.
    *