Fix internal markdown link.
Fix internal markdown link.

jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,andrewcorrigan/thrust-multi-permutation-iterator,jaredhoberock/thrust,thrust/thrust,thrust/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,jaredhoberock/thrust,thrust/thrust,jaredhoberock/thrust