/whois (realname) shows a list of player USERNAMES, not a list of player NICKNAMES

[MelonMojito]

Describe the issue:

• /whois (realname) shows a list of player USERNAMES, not a list of player NICKNAMES. This could be fixed by creating a new ArgumentType for player nicknames, and listing that in the argument.
  Expected behavior:
• /whois (realname) shows a list of the player nicknames so you can properly choose who to get the username of
  Version info:
• Version nightly-2024-11-06
  Additional Comments:
• Fixing this and making it greedy (like a greedy string etc.) would allow for the getting of nicknames with spaces in them. Invaluble for server owners and operators.