Stereo buffer may not be a good wording

*This may apply to different versions of the document. Please check and fix them accordingly.

document link : https://doc.qt.io/qt-6/qsurfaceformat.html#details

There is a term "Stereo buffer" in the document without its meaning and I could not find the exact match of it on Google either.

Based on the results on Google, I'm assuming that it means "multiple buffers" or "quad buffers" or some sort, but since this term "Stereo buffer" just shows up in the document twice without any explanation, there's no way for me to be 100% sure what it means.

For readers, having an unfamiliar words in the document is frustrating(maybe it's due to the lack of knowledge of them at this point), and worse yet, not being able to find the definition of it on the web is another and bigger frustration, which we want to avoid at all cost, in my opinion. (We want our users to think the Qt document is great, don't we?)

So I suggest that we should either change the wording of "Stereo buffer" or add some explanation on what it means.