[Feature Request] add more placeholders

[SnowCutieOwO]

• [inventory], [inv], [i], [i:slot] to show specific item or whole inventory
• [hotbar], [hb], [hb:slot] to show specific item or all items in hotbar
• [enderchest], [ec], [ec:slot] to show specific item or all items in enderchest

and maybe a command for quick show item, like /show <where> [slot] (ex: /show hotbar 1 would send [hb:1] which means first item in hotbar to chat)

:3