Fix formatting for visit/filter.rs
diff --git a/src/visit/filter.rs b/src/visit/filter.rs
index 22beb00..110ebea 100644
--- a/src/visit/filter.rs
+++ b/src/visit/filter.rs
@@ -50,7 +50,8 @@
 // Can't express these as a generic impl over all references since that would conflict with the
 // impl for Fn.
 impl<N> FilterNode<N> for &FixedBitSet
-    where FixedBitSet: VisitMap<N>
+where
+    FixedBitSet: VisitMap<N>,
 {
     fn include_node(&self, n: N) -> bool {
         self.is_visited(&n)
@@ -58,14 +59,14 @@
 }
 
 impl<N, S> FilterNode<N> for &HashSet<N, S>
-    where HashSet<N, S>: VisitMap<N>,
+where
+    HashSet<N, S>: VisitMap<N>,
 {
     fn include_node(&self, n: N) -> bool {
         self.is_visited(&n)
     }
 }
 
-
 /// A node-filtering graph adaptor.
 #[derive(Copy, Clone, Debug)]
 pub struct NodeFiltered<G, F>(pub G, pub F);