Corrected error in enum example.

slides/cours_5.md

@@ -26,7 +26,7 @@ date: "2022-11-02"
 
     ```C
     enum days d = monday;
-    (d + 2) == tuesday + tuesday; // true
+    (d + 2) == monday + monday; // true
     ```
 
 # Types énumérés (2/2)