[lab4] little fix in lab text

cfab5716 · Mikaël BRIDAY · 05e5e04b · cfab5716 · cfab5716 · cfab5716
Commit cfab5716 authored Jan 03, 2022 by Mikaël BRIDAY
--- a/lab1/lab1.pdf
+++ b/lab1/lab1.pdf
--- a/lab2/lab2.pdf
+++ b/lab2/lab2.pdf
--- a/lab3/lab3.pdf
+++ b/lab3/lab3.pdf
--- a/lab4/lab4.pdf
+++ b/lab4/lab4.pdf