Rename MWPS in system notes and related tests

app/services/system_note_service.rb

@@ -135,7 +135,7 @@ module SystemNoteService
   # Called when 'merge when build succeeds' is executed
   def merge_when_build_succeeds(noteable, project, author, last_commit)
-    body = "Enabled an automatic merge when the build for #{last_commit.to_reference(project)} succeeds"
+    body = "Enabled an automatic merge when the pipeline for #{last_commit.to_reference(project)} succeeds"
     create_note(noteable: noteable, project: project, author: author, note: body)
   end

app/views/projects/merge_requests/widget/open/_merge_when_build_succeeds.html.haml

 %h4
   Set by #{link_to_member(@project, @merge_request.merge_user, avatar: true)}
-  to be merged automatically when the build succeeds.
+  to be merged automatically when the pipeline succeeds.
 %div
   %p
     = succeed '.' do

spec/features/merge_requests/merge_when_build_succeeds_spec.rb

@@ -40,11 +40,11 @@ feature 'Merge When Build Succeeds', feature: true, js: true do
       it 'activates Merge When Build Succeeds feature' do
         expect(page).to have_link "Cancel Automatic Merge"
-        expect(page).to have_content "Set by #{user.name} to be merged automatically when the build succeeds."
+        expect(page).to have_content "Set by #{user.name} to be merged automatically when the pipeline succeeds."
         expect(page).to have_content "The source branch will not be removed."
         visit_merge_request(merge_request) # Needed to refresh the page
-        expect(page).to have_content /Enabled an automatic merge when the build for [0-9a-f]{8} succeeds/i
+        expect(page).to have_content /Enabled an automatic merge when the pipeline for [0-9a-f]{8} succeeds/i
       end
     end
   end

spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb

@@ -40,7 +40,7 @@ describe MergeRequests::MergeWhenPipelineSucceedsService do
       it 'creates a system note' do
         note = merge_request.notes.last
-        expect(note.note).to match /Enabled an automatic merge when the build for (\w+\/\w+@)?[0-9a-z]{8}/
+        expect(note.note).to match /Enabled an automatic merge when the pipeline for (\w+\/\w+@)?[0-9a-z]{8}/
       end
     end

spec/services/system_note_service_spec.rb

@@ -225,8 +225,8 @@ describe SystemNoteService, services: true do
     it_behaves_like 'a system note'
-    it "posts the Merge When Build Succeeds system note" do
-      expect(subject.note).to match  /Enabled an automatic merge when the build for (\w+\/\w+@)?[0-9a-f]{40} succeeds/
+    it "posts the 'merge when pipeline succeeds' system note" do
+      expect(subject.note).to match  /Enabled an automatic merge when the pipeline for (\w+\/\w+@)?[0-9a-f]{40} succeeds/
     end
   end
@@ -239,7 +239,7 @@ describe SystemNoteService, services: true do
     it_behaves_like 'a system note'
-    it "posts the Merge When Build Succeeds system note" do
+    it "posts the 'merge when pipeline succeeds' system note" do
       expect(subject.note).to eq  "Canceled the automatic merge"
     end
   end