Has it been reported that Umar ibn al-Khattab, may Allah be pleased with him, was told that repentance from shirk is accepted, this being in the context of discussing the repentance of the fornicator, and why was it said, "it has been accepted" instead of "it is accepted"?

Repentance is accepted for all sins as long as the repentant has not reached the rattling of the throat (death throes) and the sun has not risen from the west. If a disbeliever repents, his repentance is accepted, and what has passed is forgiven him, as Allah says: "Say to those who have disbelieved, if they cease, what has passed will be forgiven them" (Qur’an 8:38). And as the Prophet, peace and blessings be upon him, said: "The one who repents from sin is like one who has no sin."