Document that ParseCurrentRecord modifies parsed

SaneTsv.cs

@@ -278,6 +278,9 @@ public class SaneTsv
     return parsed;
   }
 
+  /// <summary>
+  /// Note: this modifies 'parsed'
+  /// </summary>
   protected static object[] ParseCurrentRecord(SaneTsv parsed, List<byte[]> fields, int line)
   {
     var parsedFields = new object[fields.Count];