Use UseSegment::Slf or UseSegment::Super when appropriate

Currently we `UseSegment::Ident` for all of the segments except the last.
E.g. `use super::foo::bar::self;` will be
`[Ident("super"), Ident("foo"), Ident("bar"), Self(None)]`.
in the current implementation. I think that this should be
`[Super(None), Ident("foo"), Ident("bar"), Self(None)]`.
instead.

I noticed this because some tests failed after updating
`rustc-ap-syntax` to 73.0.0.

src/reorder.rs

@@ -299,16 +299,24 @@ impl UseSegment {
             _ => self.clone(),
         }
     }
+
+    fn from_path_segment(path_seg: &ast::PathSegment) -> UseSegment {
+        let name = path_seg.identifier.name.as_str();
+        if name == "self" {
+            UseSegment::Slf(None)
+        } else if name == "super" {
+            UseSegment::Super(None)
+        } else {
+            UseSegment::Ident((*name).to_owned(), None)
+        }
+    }
 }
 
 impl UseTree {
     fn from_ast(a: &ast::UseTree) -> UseTree {
         let mut result = UseTree { path: vec![] };
         for p in &a.prefix.segments {
-            result.path.push(UseSegment::Ident(
-                (*p.identifier.name.as_str()).to_owned(),
-                None,
-            ));
+            result.path.push(UseSegment::from_path_segment(p));
         }
         match a.kind {
             UseTreeKind::Glob => {