Review: oop_intro.md #49

Part of #40 (Phase 1).

Native-speaker review of oop_intro.md by @Honaminto.

How to reply. Open a PR editing the French directly — one PR for this lecture, titled e.g. [oop_intro] Corrections — or leave line comments / suggestion blocks on it. Priorities: meaning errors, wrong technical terms, inconsistent terminology, unnatural French (academic register), anything in code comments that looks wrong. Ignore spacing before : ; ! ?, errors in the English, and the translation: header. A wrong term that recurs belongs on the terminology issue, not here.

Done when a PR by @Honaminto touching this file is merged, or Emile states here that the lecture needs no change. Either outcome is recorded; nothing is ticked by hand.