Update textbook.fr.md

00.brainstorming-pedagogical-teams/40.collection-existing-pedagogical-content/40.classical-mechanics/50.n4/30.en/10.main/textbook.fr.md

@@ -4,11 +4,11 @@ published: true
 routable: true
 visible: false
 lessons:
-    - slug: classical mechanics-n4-linear
+    - slug: classical-mechanics-n4-linear
       order: 1
-    - slug: classical mechanics-234-panorama
+    - slug: classical-mechanics-234-panorama
       order: 3
-    - slug: classical mechanics-n4-exchange
+    - slug: classical-mechanics-n4-exchange
       order: 3
 ---