That is what Neil Armstrong wrote before the flight, and what he fully intended to say on the Moon, but that is not what he said.
He inadvertently left out the "a" before "man," and no amount of revisionist history will change that fact, nor will excuses of an "overly sensitive VOX circuit" in his radio system that clipped the word.
He claimed in interviews that he had not decided what to say until after the landing. Then his brother later claimed Neil told him what he was gonna say? I dunno. A bunch of pedantry over the “A” doesn’t make sense to me. It’s sort of implied. You’ll never hear it. Try speaking the line, it’s not really there depending accent. Why it became a talking point is strange.