allow rustfmt to reorder imports

This wasn't a right decision in the first place, the feature flag was
broken in the last rustfmt release, and syntax highlighting of imports
is more important anyway

crates/ra_project_model/src/sysroot.rs

@@ -3,7 +3,7 @@ use std::{
     process::Command,
 };
 
-use ra_arena::{Arena, RawId, impl_arena_id};
+use ra_arena::{impl_arena_id, Arena, RawId};
 
 use crate::Result;