Add precisions to the mod-file header.

tests/optimizers/fs2000_99.mod

@@ -22,10 +22,14 @@
  * This implementation was originally written by Michel Juillard. Please note that the
  * following copyright notice only applies to this Dynare implementation of the
  * model.
+ *
+ * Uses mode_compute=99 for the One-Step method which delivers a fast and asymptotically 
+ * efficient estimator from the correction of a preliminary convergent estimator  
+ * obtained on a learning sample of size T power delta.
  */
 
 /*
- * Copyright © 2004-2023 Dynare Team
+ * Copyright © 2004-2025 Dynare Team
  *
  * This file is part of Dynare.
  *