Fix typo in parquet/page_decode.cuh (#13849)

This PR fixes a typo in the parquet page decoding doc and adds a missing doc.

Authors:
  - Xinyu Zeng (https://github.com/XinyuZeng)

Approvers:
  - Nghia Truong (https://github.com/ttnghia)
  - David Wendt (https://github.com/davidwendt)

URL: #13849

cpp/src/io/parquet/page_decode.cuh

@@ -443,8 +443,9 @@ __device__ size_type gpuInitStringDescriptors(page_state_s volatile* s,
 /**
  * @brief Decode values out of a definition or repetition stream
  *
+ * @param[out] output Level buffer output
  * @param[in,out] s Page state input/output
- * @param[in] t target_count Target count of stream values on output
+ * @param[in] target_count Target count of stream values on output
  * @param[in] t Warp0 thread ID (0..31)
  * @param[in] lvl The level type we are decoding - DEFINITION or REPETITION
  */