Enforce import grouping

Includes a few manual changes to make rustfmt behave a bit better.

crates/ruma-state-res/src/test_utils.rs

@@ -27,10 +27,9 @@ use serde_json::{
 };
 use tracing::info;
 
+pub(crate) use self::event::PduEvent;
 use crate::{auth_types_for_event, Error, Event, EventTypeExt, Result, StateMap};
 
-pub(crate) use event::PduEvent;
-
 static SERVER_TIMESTAMP: AtomicU64 = AtomicU64::new(0);
 
 pub(crate) fn do_check(