Fix some minor documentation problems.
Fix some minor documentation problems.

sdalton1/thrust,thvasilo/thrust,dachziegel/thrust,jaredhoberock/thrust,egaburov/thrust,raygit/thrust,arnabgho/thrust,mohamed-ali/thrust,xiongzhanblake/thrust_src,sarvex/thrust,zhenglaizhang/thrust,andrewcorrigan/thrust-multi-permutation-iterator,Ricardo666666/thrust,xiongzhanblake/thrust,GrimDerp/thrust,raygit/thrust,mohamed-ali/thrust,marksantos/thrust,Ricardo666666/thrust,jaredhoberock/thrust,xiongzhanblake/thrust_src,zeryx/thrust,andrewcorrigan/thrust-multi-permutation-iterator,egaburov/thrust,marksantos/thrust,thrust/thrust,sarvex/thrust,xiongzhanblake/thrust_src,zhenglaizhang/thrust,xiongzhanblake/thrust,sarvex/thrust,dachziegel/thrust,GrimDerp/thrust,GrimDerp/thrust,raygit/thrust,andrewcorrigan/thrust-multi-permutation-iterator,jaredhoberock/thrust,arnabgho/thrust,sdalton1/thrust,thrust/thrust,jaredhoberock/thrust,zeryx/thrust,thvasilo/thrust,sdalton1/thrust,marksantos/thrust,xiongzhanblake/thrust,thrust/thrust,arnabgho/thrust,Ricardo666666/thrust,jaredhoberock/thrust,thrust/thrust,thvasilo/thrust,mohamed-ali/thrust,egaburov/thrust,dachziegel/thrust,thrust/thrust,zhenglaizhang/thrust,zeryx/thrust