[names] Corrections de style et de terminologie (#80)

Native-speaker review of names.md by @Honaminto: « espace de nommage » throughout (per the official French Python documentation), « ramasse-miettes », « chaîne de documentation », « renvoyer », the Python 3 builtins module and the %run magic, French print strings in one example, calques removed and heading case fixed. Maintainer fix-up restores eight non-breaking spaces. Validated in project-translation reports/2026-09-23-fr-round2-editor-review-disposition.md.

Closes #50

Author: Honaminto