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_tt/src/buffer.rs

@@ -1,4 +1,4 @@
-use crate::{TokenTree, Subtree};
+use crate::{Subtree, TokenTree};
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 struct EntryId(usize);