Make Doxygen comments formatting consistent(#7041)

Making this PR since wrong formatting keeps getting propagated in new PRs and (sometimes) corrected in code review.

Changes:

- Ironed out the formatting of Doxygen comments to match the guidelines. 
- Removed the outdated file with formatting examples.

Authors:
  - vuule <vmilovanovic@nvidia.com>
  - Vukasin Milovanovic <vukasin.milovanovic.87@gmail.com>
  - vukasin <vmilovanovic@nvidia.com>

Approvers:
  - David
  - Karthikeyan

URL: #7041

cpp/benchmarks/synchronization/synchronization.hpp

@@ -17,7 +17,7 @@
 /**
  * @file synchronization.hpp
  * @brief This is the header file for `cuda_event_timer`.
- **/
+ */
 
 /**
  * @brief  This class serves as a wrapper for using `cudaEvent_t` as the user
@@ -54,7 +54,7 @@
     BENCHMARK(sample_cuda_benchmark)->UseManualTime();
 
 
- **/
+ */
 
 #ifndef CUDF_BENCH_SYNCHRONIZATION_H
 #define CUDF_BENCH_SYNCHRONIZATION_H
@@ -79,7 +79,7 @@ class cuda_event_timer {
    * @param[in] flush_l2_cache_ whether or not to flush the L2 cache before
    *                            every iteration.
    * @param[in] stream_ The CUDA stream we are measuring time on.
-   **/
+   */
   cuda_event_timer(benchmark::State& state,
                    bool flush_l2_cache,
                    rmm::cuda_stream_view stream = rmm::cuda_stream_default);

cpp/docs/TRANSITIONGUIDE.md

@@ -777,7 +777,7 @@ namespace experimental{
  * @param mr Memory resource used to allocate device memory for the returned
  * output column
  * @return std::unique_ptr<column> Newly allocated output column
- **/
+ */
 std::unique_ptr<column> new_function(cudf::column_view input, 
                                      cudf::mutable_column_view in_out, 
                                      cudf::table_view input_table,

cpp/include/cudf/ast/detail/linearizer.hpp

@@ -39,7 +39,6 @@ namespace detail {
  *
  * This enum is device-specific. For instance, intermediate data references are generated by the
  * linearization process but cannot be explicitly created by the user.
- *
  */
 enum class device_data_reference_type {
   COLUMN,       // A value in a table column
@@ -52,7 +51,6 @@ enum class device_data_reference_type {
  *
  * This is a POD class used to create references describing data type and locations for consumption
  * by the `row_evaluator`.
- *
  */
 struct alignas(8) device_data_reference {
   device_data_reference(device_data_reference_type reference_type,
@@ -85,7 +83,6 @@ class linearizer;
  *
  * This class is a part of a "visitor" pattern with the `linearizer` class.
  * Nodes inheriting from this class can accept visitors.
- *
  */
 class node {
   friend class detail::linearizer;
@@ -104,7 +101,6 @@ class node {
  * the nodes and constructing vectors of information that are later used by the device for
  * evaluating the abstract syntax tree as a "linear" list of operators whose input dependencies are
  * resolved into intermediate data storage in shared memory.
- *
  */
 class linearizer {
   friend class literal;

cpp/include/cudf/ast/detail/operators.hpp

@@ -931,7 +931,6 @@ struct dispatch_unary_operator_types {
 
 /**
  * @brief Functor performing a type dispatch for a unary operator.
- *
  */
 struct type_dispatch_unary_op {
   template <ast_operator op, typename F, typename... Ts>
@@ -968,7 +967,6 @@ CUDA_HOST_DEVICE_CALLABLE constexpr void unary_operator_dispatcher(ast_operator
 
 /**
  * @brief Functor to determine the return type of an operator from its input types.
- *
  */
 struct return_type_functor {
   /**
@@ -1057,7 +1055,6 @@ inline cudf::data_type ast_operator_return_type(ast_operator op,
 
 /**
  * @brief Functor to determine the arity (number of operands) of an operator.
- *
  */
 struct arity_functor {
   template <ast_operator op>

cpp/include/cudf/ast/detail/transform.cuh

@@ -126,7 +126,6 @@ struct binary_row_output : public row_output {
  * This class is designed for n-ary transform evaluation. Currently this class assumes that there's
  * only one relevant "row index" in its methods, which corresponds to a row in a single input table
  * and the same row index in an output column.
- *
  */
 struct row_evaluator {
   friend struct row_output;

cpp/include/cudf/ast/linearizer.hpp

@@ -32,7 +32,6 @@ namespace ast {
  * @brief Enum of table references.
  *
  * This determines which table to use in cases with two tables (e.g. joins).
- *
  */
 enum class table_reference {
   LEFT,   // Column index in the left table
@@ -47,7 +46,6 @@ class expression;
 
 /**
  * @brief A literal value used in an abstract syntax tree.
- *
  */
 class literal : public detail::node {
   friend class detail::linearizer;
@@ -114,7 +112,6 @@ class literal : public detail::node {
 
 /**
  * @brief A node referring to data from a column in a table.
- *
  */
 class column_reference : public detail::node {
   friend class detail::linearizer;
@@ -194,7 +191,6 @@ class column_reference : public detail::node {
 
 /**
  * @brief An expression node holds an operator and zero or more operands.
- *
  */
 class expression : public detail::node {
   friend class detail::linearizer;

cpp/include/cudf/ast/operators.hpp

@@ -21,7 +21,6 @@ namespace ast {
 
 /**
  * @brief Enum of supported operators.
- *
  */
 enum class ast_operator {
   // Binary operators

cpp/include/cudf/column/column.hpp

@@ -53,7 +53,7 @@ class column {
    * @brief Construct a new column by deep copying the contents of `other`.
    *
    * @param other The column to copy
-   **/
+   */
   column(column const& other);
 
   /**
@@ -77,7 +77,7 @@ class column {
    * After the move, `other.size() == 0` and `other.type() = {EMPTY}`
    *
    * @param other The column whose contents will be moved into the new column
-   **/
+   */
   column(column&& other) noexcept;
 
   /**
@@ -95,7 +95,7 @@ class column {
    * `UNKNOWN_NULL_COUNT` to indicate that the null count should be computed on
    * the first invocation of `null_count()`.
    * @param children Optional, vector of child columns
-   **/
+   */
   template <typename B1, typename B2 = rmm::device_buffer>
   column(data_type dtype,
          size_type size,

cpp/include/cudf/column/column_device_view.cuh

@@ -50,7 +50,6 @@ namespace detail {
  * not-obvious computation of null count, which could lead to undesirable performance issues.
  * This information is also generally not needed in device code, and on the host-side
  * is easily accessible from the associated column_view.
- *
  */
 class alignas(16) column_device_view_base {
  public:

cpp/include/cudf/column/column_factories.hpp

@@ -583,7 +583,6 @@ std::unique_ptr<cudf::column> make_lists_column(
  * @param[in] null_mask The bits specifying the null struct values in the column.
  * @param[in] stream Optional stream for use with all memory allocation and device kernels.
  * @param[in] mr Optional resource to use for device memory allocation.
- *
  */
 std::unique_ptr<cudf::column> make_structs_column(
   size_type num_rows,