Write doc for complex power of a matrix.
Write doc for complex power of a matrix.

ritsu1228/eigen,ritsu1228/eigen,pasuka/eigen,ROCmSoftwarePlatform/hipeigen,Zefz/eigen,toastedcrumpets/eigen,Zefz/eigen,toastedcrumpets/eigen,ritsu1228/eigen,TSC21/Eigen,pasuka/eigen,TSC21/Eigen,Zefz/eigen,toastedcrumpets/eigen,ROCmSoftwarePlatform/hipeigen,TSC21/Eigen,Zefz/eigen,ROCmSoftwarePlatform/hipeigen,ROCmSoftwarePlatform/hipeigen,pasuka/eigen,pasuka/eigen,ritsu1228/eigen,ritsu1228/eigen,toastedcrumpets/eigen,TSC21/Eigen,pasuka/eigen