Address some clippy comments (#993)

Author: dcherian

icechunk/src/format/manifest.rs

@@ -378,11 +378,9 @@ fn lookup_ref<'a>(
     array_manifest: generated::ArrayManifest<'a>,
     coord: &ChunkIndices,
 ) -> Option<generated::ChunkRef<'a>> {
-    let res =
-        array_manifest.refs().lookup_by_key(coord.0.as_slice(), |chunk_ref, coords| {
-            chunk_ref.index().iter().cmp(coords.iter().copied())
-        });
-    res
+    array_manifest.refs().lookup_by_key(coord.0.as_slice(), |chunk_ref, coords| {
+        chunk_ref.index().iter().cmp(coords.iter().copied())
+    })
 }
 
 struct PayloadIterator {

icechunk/src/storage/object_store.rs

@@ -790,14 +790,11 @@ impl ObjectStoreBackend for S3ObjectStoreBackend {
                     .with_access_key_id(credentials.access_key_id.clone())
                     .with_secret_access_key(credentials.secret_access_key.clone());
 
-                let builder =
-                    if let Some(session_token) = credentials.session_token.as_ref() {
-                        builder.with_token(session_token.clone())
-                    } else {
-                        builder
-                    };
-
-                builder
+                if let Some(session_token) = credentials.session_token.as_ref() {
+                    builder.with_token(session_token.clone())
+                } else {
+                    builder
+                }
             }
             Some(S3Credentials::Anonymous) => builder.with_skip_signature(true),
             // TODO: Support refreshable credentials