Fix handson code convention

1-ProceduralProgramming/4b-hands-on.ipynb

1-ProceduralProgramming/6b-hands-on.ipynb

2-ObjectProgramming/1b-hands-on.ipynb

2-ObjectProgramming/2b-hands-on.ipynb

2-ObjectProgramming/4b-hands-on.ipynb

2-ObjectProgramming/7b-hands-on.ipynb

4-Templates/1b-hands-on.ipynb

5-UsefulConceptsAndSTL/1b-hands-on.ipynb

5-UsefulConceptsAndSTL/6b-hands-on.ipynb

6-InRealEnvironment/2b-hands-on.ipynb

HandsOn/1-ProceduralProgramming/Solution/exercice1.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice10.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice11.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice12.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice2.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice3.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice4.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice5.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice6.cpp

HandsOn/1-ProceduralProgramming/Solution/exercice7.cpp