Fix Doxygen documentation warnings.

Author: breyerml

docs/resources/dirs.dox

@@ -400,7 +400,7 @@
  * @dir include/plssvm/backends/HPX/detail
  * @author Alexander Van Craen
  * @author Marcel Breyer
- * @authir Alexander Strack
+ * @author Alexander Strack
  * @copyright 2018-today The PLSSVM project - All Rights Reserved
  * @license This file is part of the PLSSVM project which is released under the MIT license.
  *          See the LICENSE.md file in the project root for full license information.
@@ -436,7 +436,7 @@
  * @dir include/plssvm/backends/HPX/kernel/cg_implicit
  * @author Alexander Van Craen
  * @author Marcel Breyer
- * @author Alexander Strack 
+ * @author Alexander Strack
  * @copyright 2018-today The PLSSVM project - All Rights Reserved
  * @license This file is part of the PLSSVM project which is released under the MIT license.
  *          See the LICENSE.md file in the project root for full license information.

include/plssvm/backends/Kokkos/detail/constexpr_available_execution_spaces.hpp

@@ -13,8 +13,11 @@
 #ifndef PLSSVM_BACKENDS_KOKKOS_DETAIL_CONSTEXPR_AVAILABLE_EXECUTION_SPACES_HPP_
 #define PLSSVM_BACKENDS_KOKKOS_DETAIL_CONSTEXPR_AVAILABLE_EXECUTION_SPACES_HPP_
 
-// if the variable isn't set, no Kokkos execution space is available
-// -> explicitly set it to 0!
+/**
+ * @def PLSSVM_KOKKOS_BACKEND_NUM_AVAILABLE_EXECUTION_SPACES
+ * @brief Set the macro `PLSSVM_KOKKOS_BACKEND_NUM_AVAILABLE_EXECUTION_SPACES` to 0 if it isn't already defined, i.e., no Kokkos execution space is available.
+ *        Will normally be propagated by CMake with the number of available Kokkos execution spaces.
+ */
 #if !defined(PLSSVM_KOKKOS_BACKEND_NUM_AVAILABLE_EXECUTION_SPACES)
     #define PLSSVM_KOKKOS_BACKEND_NUM_AVAILABLE_EXECUTION_SPACES 0
 #endif

include/plssvm/environment.hpp

@@ -458,7 +458,8 @@ inline std::vector<backend_type> finalize() {
 class [[nodiscard]] scope_guard {
   public:
     /**
-     * @copydoc initialize()
+     * @brief Initialize all **available** backends.
+     * @details Only initializes backends that are currently uninitialized.
      */
     scope_guard() {
         backends_ = initialize();
@@ -473,7 +474,10 @@ class [[nodiscard]] scope_guard {
     }
 
     /**
-     * @copydoc initialize(int &, char **)
+     * @brief Initialize all **available** backends.
+     * @details Only initializes backends that are currently uninitialized.
+     * @param[in,out] argc the number of provided command line arguments
+     * @param[in,out] argv the provided command line arguments
      */
     scope_guard(int &argc, char **argv) {
         backends_ = initialize(argc, argv);