move exponential backoff util to different submod

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/rooms/event_handler/fetch_and_handle_outliers.rs

@@ -6,7 +6,7 @@ use std::{
 
 use conduwuit::{
 	debug, debug_error, debug_warn, implement, pdu, trace,
-	utils::math::continue_exponential_backoff_secs, warn, PduEvent,
+	utils::continue_exponential_backoff_secs, warn, PduEvent,
 };
 use futures::TryFutureExt;
 use ruma::{

src/service/rooms/event_handler/handle_prev_pdu.rs

@@ -5,7 +5,7 @@ use std::{
 };
 
 use conduwuit::{
-	debug, implement, utils::math::continue_exponential_backoff_secs, Err, PduEvent, Result,
+	debug, implement, utils::continue_exponential_backoff_secs, Err, PduEvent, Result,
 };
 use ruma::{CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName};