Suggestion: Timer for >>raidmode on

when someone does `>>raidmode on `, it should turn on raidmode for the default amount of time. If the moderator does `>>raidmode on `, it should turn on raidmode for the time specified, as sometimes many bots raid your servers, which gets annoying to keep turning on >>raidmode

Start by locating the handler for the `>raidmode` command; the issue names no file or test path. Verify both the default-duration form and the explicit-time form, including the reason, and confirm that raidmode ends after the requested duration.

Written by the indexing model from the issue text.