Update cheatsheet.fr.md

01.curriculum/01.physics-chemistry-biology/03.niv3/05.math-tools-for-physics/04.differential-operators/04.curl/cheatsheet.fr.md

@@ -1,6 +1,7 @@
 ---
 title: the curl vector
 published: true
+routable: true
 visible: true
 lessons:
   - slug: gravitation-electrostat-magnetostat