Edit float16 doc (#5851)
Edit float16 doc (#5851)

* Add survey of support of half in different CUDA versions

* small fix

baidu/Paddle,reyoung/Paddle,Canpio/Paddle,baidu/Paddle,reyoung/Paddle,Canpio/Paddle,Canpio/Paddle,putcn/Paddle,chengduoZH/Paddle,baidu/Paddle,lcy-seso/Paddle,QiJune/Paddle,putcn/Paddle,chengduoZH/Paddle,tensor-tang/Paddle,pkuyym/Paddle,pkuyym/Paddle,lcy-seso/Paddle,chengduoZH/Paddle,putcn/Paddle,QiJune/Paddle,tensor-tang/Paddle,luotao1/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,Canpio/Paddle,lcy-seso/Paddle,baidu/Paddle,PaddlePaddle/Paddle,lcy-seso/Paddle,QiJune/Paddle,Canpio/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,reyoung/Paddle,baidu/Paddle,pkuyym/Paddle,tensor-tang/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,reyoung/Paddle,putcn/Paddle,PaddlePaddle/Paddle,lcy-seso/Paddle,lcy-seso/Paddle,tensor-tang/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,luotao1/Paddle,pkuyym/Paddle,QiJune/Paddle,luotao1/Paddle,pkuyym/Paddle,Canpio/Paddle,QiJune/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,pkuyym/Paddle,tensor-tang/Paddle,QiJune/Paddle,jacquesqiao/Paddle,putcn/Paddle,luotao1/Paddle,Canpio/Paddle,jacquesqiao/Paddle,jacquesqiao/Paddle,jacquesqiao/Paddle,chengduoZH/Paddle,jacquesqiao/Paddle,putcn/Paddle,jacquesqiao/Paddle,luotao1/Paddle,Canpio/Paddle