Fix ruby warnings

This fixes following warnings:

```
test/models/variant_test.rb:11: warning: ambiguous first argument; put parentheses or a space even after `/' operator
lib/active_storage/attached/macros.rb:63: warning: instance variable @active_storage_attached_highlights not initialized
lib/active_storage/attached/macros.rb:25: warning: instance variable @active_storage_attached_avatar not initialized
```

2 files changed, 3 insertions, 3 deletions

diff --git a/activestorage/test/controllers/direct_uploads_controller_test.rb b/activestorage/test/controllers/direct_uploads_controller_test.rb
index e056b629bb..4f335c7759 100644
--- a/activestorage/test/controllers/direct_uploads_controller_test.rb
+++ b/activestorage/test/controllers/direct_uploads_controller_test.rb
@@ -25,7 +25,7 @@ if SERVICE_CONFIGURATIONS[:s3] && SERVICE_CONFIGURATIONS[:s3][:access_key_id].pr
         assert_equal checksum, details["checksum"]
         assert_equal "text/plain", details["content_type"]
         assert_match SERVICE_CONFIGURATIONS[:s3][:bucket], details["direct_upload"]["url"]
-        assert_match /s3\.(\S+)?amazonaws\.com/, details["direct_upload"]["url"]
+        assert_match(/s3\.(\S+)?amazonaws\.com/, details["direct_upload"]["url"])
         assert_equal({ "Content-Type" => "text/plain", "Content-MD5" => checksum }, details["direct_upload"]["headers"])
       end
     end
@@ -115,7 +115,7 @@ class ActiveStorage::DiskDirectUploadsControllerTest < ActionDispatch::Integrati
       assert_equal 6, details["byte_size"]
       assert_equal checksum, details["checksum"]
       assert_equal "text/plain", details["content_type"]
-      assert_match /rails\/active_storage\/disk/, details["direct_upload"]["url"]
+      assert_match(/rails\/active_storage\/disk/, details["direct_upload"]["url"])
       assert_equal({ "Content-Type" => "text/plain" }, details["direct_upload"]["headers"])
     end
   end
diff --git a/activestorage/test/controllers/variants_controller_test.rb b/activestorage/test/controllers/variants_controller_test.rb
index fa8d15977d..b3ff83e95e 100644
--- a/activestorage/test/controllers/variants_controller_test.rb
+++ b/activestorage/test/controllers/variants_controller_test.rb
@@ -12,7 +12,7 @@ class ActiveStorage::VariantsControllerTest < ActionDispatch::IntegrationTest
       signed_blob_id: @blob.signed_id,
       variation_key: ActiveStorage::Variation.encode(resize: "100x100"))
 
-    assert_redirected_to /racecar.jpg\?.*disposition=inline/
+    assert_redirected_to(/racecar.jpg\?.*disposition=inline/)
 
     image = read_image_variant(@blob.variant(resize: "100x100"))
     assert_equal 100, image.width