This change removes 8 warnings from debug.txt every time server starts.
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_hook` at @/minetest/mods/irc_commands/init.lua:14
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_hook` at @/minetest/mods/irc_commands/init.lua:23
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_hook` at @/minetest/mods/irc_commands/init.lua:27
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_hook` at @/minetest/mods/irc_commands/init.lua:31
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_bot_command` at @/minetest/mods/irc_commands/init.lua:35
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_bot_command` at @/minetest/mods/irc_commands/init.lua:77
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_bot_command` at @/minetest/mods/irc_commands/init.lua:91
2018-06-12 11:17:25: WARNING[Main]: Deprecated use of colon notation when calling method `register_bot_command` at @/minetest/mods/irc_commands/init.lua:118