Apply automatic rubocop fixes

spec/views/execution_environments/shell.html.slim_spec.rb

@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
 describe 'execution_environments/shell.html.slim' do
   let(:execution_environment) { FactoryBot.create(:ruby) }
 
-  before(:each) do
+  before do
     assign(:execution_environment, execution_environment)
     render
   end

spec/views/exercises/implement.html.slim_spec.rb

@@ -1,11 +1,13 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
 describe 'exercises/implement.html.slim' do
   let(:exercise) { FactoryBot.create(:fibonacci) }
   let(:files) { exercise.files.visible }
-  let(:non_binary_files) { files.reject { |file| file.file_type.binary? } }
+  let(:non_binary_files) { files.reject {|file| file.file_type.binary? } }
 
-  before(:each) do
+  before do
     assign(:current_user, FactoryBot.create(:admin))
     assign(:exercise, exercise)
     assign(:files, files)