Standardize TODO/FIXME comments to Doxygen \todo format

Convert informal TODO and FIXME comments to Doxygen-recognized
      \todo format.

      - // TODO comments → //! \todo ...
      - // FIXME comments → //! \todo ...
      - /** @todo ... */ blocks → //! \todo ...
      - @brief TODO: placeholders → //! \todo (moved outside doc blocks)

libcockatrice_settings/libcockatrice/settings/card_database_settings.h

@@ -2,8 +2,8 @@
  * @file card_database_settings.h
  * @ingroup CardDatabase
  * @ingroup CardSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef CARDDATABASESETTINGS_H
 #define CARDDATABASESETTINGS_H

libcockatrice_settings/libcockatrice/settings/card_override_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file card_override_settings.h
  * @ingroup CardSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef COCKATRICE_CARD_OVERRIDE_SETTINGS_H
 #define COCKATRICE_CARD_OVERRIDE_SETTINGS_H

libcockatrice_settings/libcockatrice/settings/debug_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file debug_settings.h
  * @ingroup CoreSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef DEBUG_SETTINGS_H
 #define DEBUG_SETTINGS_H

libcockatrice_settings/libcockatrice/settings/download_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file download_settings.h
  * @ingroup NetworkSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef COCKATRICE_DOWNLOADSETTINGS_H
 #define COCKATRICE_DOWNLOADSETTINGS_H

libcockatrice_settings/libcockatrice/settings/game_filters_settings.h

@@ -2,8 +2,8 @@
  * @file game_filters_settings.h
  * @ingroup Lobby
  * @ingroup GameSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef GAMEFILTERSSETTINGS_H
 #define GAMEFILTERSSETTINGS_H

libcockatrice_settings/libcockatrice/settings/layouts_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file layouts_settings.h
  * @ingroup CoreSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef LAYOUTSSETTINGS_H
 #define LAYOUTSSETTINGS_H

libcockatrice_settings/libcockatrice/settings/message_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file message_settings.h
  * @ingroup NetworkSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef MESSAGESETTINGS_H
 #define MESSAGESETTINGS_H

libcockatrice_settings/libcockatrice/settings/recents_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file recents_settings.h
  * @ingroup DeckSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef RECENTS_SETTINGS_H
 #define RECENTS_SETTINGS_H

libcockatrice_settings/libcockatrice/settings/servers_settings.h

@@ -1,8 +1,8 @@
 /**
  * @file servers_settings.h
  * @ingroup NetworkSettings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef SERVERSSETTINGS_H
 #define SERVERSSETTINGS_H

libcockatrice_settings/libcockatrice/settings/settings_manager.h

@@ -1,8 +1,8 @@
 /**
  * @file settings_manager.h
  * @ingroup Settings
- * @brief TODO: Document this.
  */
+//! \todo Document this file.
 
 #ifndef SETTINGSMANAGER_H
 #define SETTINGSMANAGER_H