fix: crash by trying to autocomplete some commands

[ThisAMJ]

Too lazy to understand how CON_COMMAND_AUTOCOMPLETEFILE is meant to work, so I'll just take the easy way out :)

[mlugg]

yeah that's an old bullshit system - it's using the game's file autocompletion system but that system is fucked pr good but am amending to also delete the now-unused macro