Quran, 10:5 - He is the One who rendered the sun radiant, and the moon a light, and He designed its phases that you may learn to count the years and to calculate. GOD did not create all this, except for a specific purpose. He explains the revelations for people who know.
Pretty cut and dry.
Is the moon not a light? Now, the real crux of this and I assume it's what you are trying to get at, is that the moon itself is not a source of light. If that's what you are saying then you are 100% right and the Quran agrees with you.
The verse you quote is from surah Younus. Now, I'm not sure if you have done so n purpose or out of ignorance (I would like to believe the latter) but the translation is not accurate. There are 2 different words used, in Arabic, to describe the lights of the sun and the moon. If the Quran, mistaken as it is in your claim, had used the same word, I would agree that there was a belief that the moon was a source of light. However, the Quran does not make that mistake.
The word used to describe the suns light is diyaan, meaning a brilliant light/a source of light. Yet a different word is used to describe the light of the moon, noorun, meaning light but not of it's own, a reflection if you will. If you believe God had made a mistake, why did he not use the same words for both forms of light?
To go even deeper, the true context of this verse is describing the human perception of time and space. Of how you or I view the universe and to us, both the sun and the moon provide light, even in this regard the Quran is spot on. So again, there is no mistake here except the one perceived by someone who does not fully understand what they are reading.
Now, just to further alleviate any doubts, in another surah (The Criterion) which has been numbered as the 25th surah, verse 61, a more thought provoking verse, where Allah described the sun as sirajah, meaning lamp. What does a lamp do? It originates light. And then goes onto describe the moon as muneera, which means shining. When something shines, it is picking up and reflecting light from else where, like the little sparkles kids use to decorate their posters, they shine, do they not?
If there was a mistake, the arabic words for lamp and light would be same for the moon and the sun. So, as you can see, it has been made plain to you.
I will leave you with another verse from the Quran:
"And those who have no knowledge say: "Why does not Allah speak to us (face to face) or why does not a sign come to us?" So said the people before them words of similar import. Their hearts are alike, We have indeed made plain the signs for people who believe with certainty."
