Make Rubocop happier about ActiveStorage

Running `rubocop activestorage` before this commit resulted in 20 offenses.
This commit only fixes:

- Trailing whitespace detected
- Space inside } missing
- Put one space between the method name and the first argument.

The other offenses are left since they are intentional according to
@georgeclaghorn (https://github.com/rails/rails/pull/30061#issuecomment-319999190)

activestorage/activestorage.gemspec

@@ -27,4 +27,4 @@ Gem::Specification.new do |s|
 
   s.add_dependency "actionpack", version
   s.add_dependency "activerecord", version
-end
+end

activestorage/app/models/active_storage/attachment.rb

@@ -1,7 +1,7 @@
 require "active_storage/blob"
 require "active_support/core_ext/module/delegation"
 
-# Attachments associate records with blobs. Usually that's a one record-many blobs relationship, 
+# Attachments associate records with blobs. Usually that's a one record-many blobs relationship,
 # but it is possible to associate many different records with the same blob. If you're doing that,
 # you'll want to declare with `has_one/many_attached :thingy, dependent: false`, so that destroying
 # any one record won't destroy the blob as well. (Then you'll need to do your own garbage collecting, though).

activestorage/app/models/active_storage/variation.rb

@@ -1,6 +1,6 @@
 require "active_support/core_ext/object/inclusion"
 
-# A set of transformations that can be applied to a blob to create a variant. This class is exposed via 
+# A set of transformations that can be applied to a blob to create a variant. This class is exposed via
 # the `ActiveStorage::Blob#variant` method and should rarely be used directly.
 #
 # In case you do need to use this directly, it's instantiated using a hash of transformations where

activestorage/config/routes.rb

@@ -9,7 +9,7 @@ Rails.application.routes.draw do
   resolve("ActiveStorage::Attachment") { |attachment| route_for(:rails_blob, attachment.blob) }
 
 
-  get  "/rails/active_storage/variants/:signed_blob_id/:variation_key/*filename" => "active_storage/variants#show", as: :rails_blob_variation
+  get "/rails/active_storage/variants/:signed_blob_id/:variation_key/*filename" => "active_storage/variants#show", as: :rails_blob_variation
 
   direct :rails_variant do |variant|
     signed_blob_id = variant.blob.signed_id

activestorage/test/service/s3_service_test.rb

@@ -35,7 +35,7 @@ if SERVICE_CONFIGURATIONS[:s3] && SERVICE_CONFIGURATIONS[:s3][:access_key_id].pr
     end
 
     test "uploading with server-side encryption" do
-      config  = SERVICE_CONFIGURATIONS.deep_merge(s3: { upload: { server_side_encryption: "AES256" }})
+      config  = SERVICE_CONFIGURATIONS.deep_merge(s3: { upload: { server_side_encryption: "AES256" } })
       service = ActiveStorage::Service.configure(:s3, config)
 
       begin