M9-2-Principles-02-AboutClassMethodsAndRegistration typo

[MarieCollin]

https://github.com/pharo-mooc/AdvancedOODesign/blob/master/__results.luc/M9-2-Principles-02-AboutClassMethodsAndRegistration.pdf du 15/05

• p9: suggestion for the last bullet point: make reference to the lecture subject rather than a reference to the lecture positionning in the mooc ?

[LucFabresse]

ok changed.