leader_scheduler: replace older terminology with ticks, slots and epochs

src/db_window.rs

@@ -55,7 +55,7 @@ pub fn repair(
             // 1) The replay stage hasn't caught up to the "consumed" entries we sent,
             // in which case it will eventually catch up
             //
-            // 2) We are on the border between seed_rotation_intervals, so the
+            // 2) We are on the border between ticks_per_epochs, so the
             // schedule won't be known until the entry on that cusp is received
             // by the replay stage (which comes after this stage). Hence, the next
             // leader at the beginning of that next epoch will not know they are the