Add categorical data support to GPU Hist. (#6164)

src/common/hist_util.cu

@@ -178,7 +178,7 @@ void ProcessBatch(int device, MetaInfo const &info, const SparsePage &page,
   dh::XGBCachingDeviceAllocator<char> alloc;
   const auto& host_data = page.data.ConstHostVector();
   dh::device_vector<Entry> sorted_entries(host_data.begin() + begin,
-                                                  host_data.begin() + end);
+                                          host_data.begin() + end);
   thrust::sort(thrust::cuda::par(alloc), sorted_entries.begin(),
                sorted_entries.end(), detail::EntryCompareOp());