Preserve attributes for imports_granularity=Item

Fixes #5030

Author: narpfel

src/imports.rs

@@ -608,7 +608,7 @@ impl UseTree {
                             span: self.span,
                             list_item: None,
                             visibility: self.visibility.clone(),
-                            attrs: None,
+                            attrs: self.attrs.clone(),
                         });
                     }
                 }

tests/source/issue-5030.rs

@@ -0,0 +1,7 @@
+// rustfmt-imports_granularity: Item
+
+#[cfg(feature = "foo")]
+use std::collections::{
+    HashMap,
+    HashSet,
+};

tests/target/issue-5030.rs

@@ -0,0 +1,6 @@
+// rustfmt-imports_granularity: Item
+
+#[cfg(feature = "foo")]
+use std::collections::HashMap;
+#[cfg(feature = "foo")]
+use std::collections::HashSet;