Fix RSpec/ContextWording cop (#24739)

spec/controllers/activitypub/inboxes_controller_spec.rb

@@ -21,7 +21,7 @@ RSpec.describe ActivityPub::InboxesController, type: :controller do
         expect(response).to have_http_status(202)
       end
 
-      context 'for a specific account' do
+      context 'with a specific account' do
         subject(:response) { post :create, params: { account_username: account.username }, body: '{}' }
 
         let(:account) { Fabricate(:account) }