Fix doxygen warnings.

client/mysqldump.c:
  Fix doxygen warnings
mysys/test_charset.c:
  Fix doxygen warnings
sql/event_db_repository.cc:
  Fix doxygen warnings
sql/events.cc:
  Fix doxygen warnings
sql/events.h:
  Fix doxygen warnings
sql/item_create.cc:
  Fix doxygen warnings, style.
sql/item_create.h:
  Fix coding style.
sql/item_subselect.cc:
  Fix doxygen warnings
sql/lock.cc:
  Fix doxygen warnings
sql/sp.cc:
  Fix doxygen warnings
sql/sp_head.h:
  Fix doxygen warnings
sql/sql_analyse.cc:
  Fix doxygen warnings
sql/sql_analyse.h:
  Fix doxygen warnings
sql/sql_base.cc:
  Fix doxygen warnings
sql/sql_db.cc:
  Fix doxygen warnings
sql/sql_lex.cc:
  Fix doxygen warnings
sql/sql_lex.h:
  Fix doxygen warnings
sql/sql_parse.cc:
  Fix doxygen warnings
sql/sql_plugin.cc:
  Fix doxygen warnings
sql/sql_prepare.cc:
  Fix doxygen warnings
sql/sql_show.cc:
  Fix doxygen warnings
sql/sql_trigger.cc:
  Fix doxygen warnings
sql/sql_update.cc:
  Fix doxygen warnings
sql/table.h:
  Fix doxygen warnings

sql/sql_db.cc

@@ -1350,7 +1350,7 @@ static void mysql_change_db_impl(THD *thd,
   @brief Change the current database.
 
   @param thd          thread handle
-  @param name         database name
+  @param new_db_name  database name
   @param force_switch if this flag is set (TRUE), mysql_change_db() will
                       switch to NULL db if the specified database is not
                       available anymore. Corresponding warning will be