Update annex.fr.md

00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.fr.md

@@ -83,8 +83,8 @@ Sont proposées les catégories suivantes, mais à débattre :
 ! A lensball is a simple physical system: a sphere of glass of refractive index $`n=1.5`$ and of radius $`R=5\;cm`$.
 !
 ! A ball lensball is placed in front of a painting. Depending on the position of the observer or the camera, 
-the optical system (the sequence of simple optical elements crossed by light between the physical object
-and the observed image) that forms the image differs.
+! the optical system (the sequence of simple optical elements crossed by light between the physical object
+! and the observed image) that forms the image differs.
 !
 ! Observe the 3 images of the painting given by the lensball :
 !