Swift: Add models-as-data local flow sources as well.

Author: geoffw0

swift/ql/lib/codeql/swift/dataflow/FlowSources.qll

@@ -25,6 +25,15 @@ abstract class LocalFlowSource extends FlowSource { }
  */
 abstract class RemoteFlowSource extends FlowSource { }
 
+/**
+ * A data flow source of local user input that is defined through 'models as data'.
+ */
+private class ExternalLocalFlowSource extends RemoteFlowSource {
+  ExternalLocalFlowSource() { sourceNode(this, "local") }
+
+  override string getSourceType() { result = "external" }
+}
+
 /**
  * A data flow source of remote user input that is defined through 'models as data'.
  */