[3.13] gh-139933: correctly suggest attributes for classes with a custom `__dir__` (GH-139950) (GH-145827) (GH-145833)

(cherry picked from commit 4722202a1a81974089801e6173d269836b6a074f)
(cherry picked from commit 0a80015ac26d60bff54f57ce9f73ffc5386249b1)

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>