C#: Relax models as data type name validation to accept parenthesis (needed for extension types).

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll

@@ -214,7 +214,7 @@ module ModelValidation {
       not namespace.regexpMatch("[a-zA-Z0-9_\\.]+") and
       result = "Dubious namespace \"" + namespace + "\" in " + pred + " model."
       or
-      not type.regexpMatch("[a-zA-Z0-9_<>,\\+]+") and
+      not type.regexpMatch("[a-zA-Z0-9_<>,\\(\\)\\+]+") and
       result = "Dubious type \"" + type + "\" in " + pred + " model."
       or
       not name.regexpMatch("[a-zA-Z0-9_<>,\\.]*") and