Set playlist repeat on or off

Turn repeat on or off for the running playlist without starting, stopping or restarting it - the API equivalent of the Repeat checkbox in the web UI. {Repeat} may be true/false or 1/0. The new setting is read when the playlist reaches the end of its current loop, and is reflected immediately in repeat_mode from GET /api/fppd/status. Repeat belongs to a playlist that is actually running, so this returns {"Status": "Error"} when the player is idle, when {Repeat} is not one of true/false/1/0, or when fppd cannot be reached; use the repeat flag on GET /api/playlist/{PlaylistName}/start/{Repeat} to start a playlist repeating.