Improve docs and specs related to pages artifacts

doc/user/project/pages/getting_started_part_four.md

@@ -134,7 +134,7 @@ configuration for our example. On the steps below, we'll refine
 the script by adding extra options to our GitLab CI.
 
 Artifacts will be automatically deleted once GitLab Pages got deployed.
-You can preserve artifacts for limited time by specifying expiry time.
+You can preserve artifacts for limited time by specifying the expiry time.
 
 ### Image
 

spec/services/projects/update_pages_service_spec.rb

@@ -26,7 +26,7 @@ describe Projects::UpdatePagesService do
         build.update_attributes(artifacts_metadata: metadata)
       end
 
-      context 'artifacts' do
+      describe 'pages artifacts' do
         context 'with expiry date' do
           before do
             build.artifacts_expire_in = "2 days"
@@ -34,6 +34,7 @@ describe Projects::UpdatePagesService do
 
           it "doesn't delete artifacts" do
             expect(execute).to eq(:success)
+
             expect(build.reload.artifacts_file?).to eq(true)
           end
         end
@@ -41,6 +42,7 @@ describe Projects::UpdatePagesService do
         context 'without expiry date' do
           it "does delete artifacts" do
             expect(execute).to eq(:success)
+
             expect(build.reload.artifacts_file?).to eq(false)
           end
         end