improve Swarm docs and change an indexing warning to a debug log

azalea-entity/src/plugin/indexing.rs

@@ -224,7 +224,9 @@ pub fn remove_despawned_entities_from_indexes(
             warn!("Tried to remove entity {entity:?} from the uuid index but it was not there.");
         }
         if instance.entity_by_id.remove(minecraft_id).is_none() {
-            warn!("Tried to remove entity {entity:?} from the id index but it was not there.");
+            debug!(
+                "Tried to remove entity {entity:?} from the id index but it was not there. This may be expected if you're in a shared instance."
+            );
         }
 
         // remove it from every client's EntityIdIndex

azalea/src/swarm/mod.rs

@@ -35,6 +35,8 @@ use crate::{BoxHandleFn, DefaultBotPlugins, HandleFn, JoinOpts, NoState, StartEr
 /// A swarm is a way to conveniently control many bots at once, while also
 /// being able to control bots at an individual level when desired.
 ///
+/// It can safely be cloned, so there should be no need to wrap them in a Mutex.
+///
 /// Swarms are created from [`SwarmBuilder`].
 ///
 /// Clients can be added to the swarm later via [`Swarm::add`], and can be