cosmetic only, one notebook still had jupytext metadata

Author: parmentelat

notebooks/tps/boids/.teacher/README-boids-corrige-nb.md

@@ -1,9 +1,5 @@
 ---
 jupytext:
-  cell_metadata_filter: all, -hidden, -heading_collapsed, -run_control, -trusted
-  notebook_metadata_filter: all, -jupytext.text_representation.jupytext_version, -jupytext.text_representation.format_version,
-    -language_info.version, -language_info.codemirror_mode.version, -language_info.codemirror_mode,
-    -language_info.file_extension, -language_info.mimetype, -toc
   text_representation:
     extension: .md
     format_name: myst