C#: Allow for explicit interface names in MaD consistency check

Author: hvitved

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

@@ -228,7 +228,7 @@ module ModelValidation {
       not type.regexpMatch("[a-zA-Z0-9_<>,\\+]+") and
       result = "Dubious type \"" + type + "\" in " + pred + " model."
       or
-      not name.regexpMatch("[a-zA-Z0-9_<>,]*") and
+      not name.regexpMatch("[a-zA-Z0-9_<>,\\.]*") and
       result = "Dubious member name \"" + name + "\" in " + pred + " model."
       or
       not signature.regexpMatch("|\\([a-zA-Z0-9_<>\\.\\+\\*,\\[\\]]*\\)") and