Use unrolled partition for _Float16

Author: sterrettm2

src/avx512fp16-16bit-qsort.hpp

@@ -22,7 +22,7 @@ struct zmm_vector<_Float16> {
     using opmask_t = __mmask32;
     static const uint8_t numlanes = 32;
     static constexpr int network_sort_threshold = 128;
-    static constexpr int partition_unroll_factor = 0;
+    static constexpr int partition_unroll_factor = 8;
     static constexpr simd_type vec_type = simd_type::AVX512;
 
     using swizzle_ops = avx512_16bit_swizzle_ops;