fmt broke this test

Author: Vanille-N

tests/fail/tree_borrows/fnentry_invalidation.stderr

@@ -14,8 +14,8 @@ LL |     let z = &mut x as *mut i32;
 help: the accessed tag <TAG> then transitioned from Reserved to Active due to a child write access at offsets [0x0..0x4]
   --> $DIR/fnentry_invalidation.rs:LL:CC
    |
-LL |     unsafe { *z = 1; }
-   |              ^^^^^^
+LL |         *z = 1;
+   |         ^^^^^^
    = help: this corresponds to an activation
 help: the accessed tag <TAG> then transitioned from Active to Frozen due to a foreign read access at offsets [0x0..0x4]
   --> $DIR/fnentry_invalidation.rs:LL:CC