Merge branch 'radhwan.hassine-master-patch-17356' into 'master'

Update cours_11.md

See merge request algorithmique/cours!55

slides/cours_11.md

@@ -221,7 +221,6 @@ void stack_pop(stack *s, int *val) {
     element *tmp = *s;
     *s = (*s)->next;
     free(tmp);
-    return val;
 }
 ```