Port fast-forward merge request setting from EE

app/views/projects/_merge_request_fast_forward_settings.html.haml

+- form = local_assigns.fetch(:form)
+- project = local_assigns.fetch(:project)
+
+.radio
+  = label_tag :project_merge_method_ff do
+    = form.radio_button :merge_method, :ff, class: "js-merge-method-radio"
+    %strong Fast-forward merge
+    %br
+    %span.descr
+      No merge commits are created and all merges are fast-forwarded, which means that merging is only allowed if the branch could be fast-forwarded.
+    %br
+    %span.descr
+      When fast-forward merge is not possible, the user must first rebase locally.

app/views/projects/_merge_request_merge_settings.html.haml

 - form = local_assigns.fetch(:form)
 
-.form-group
-  = label_tag :merge_method_merge, class: 'label-light' do
-    Merge method
-  .radio
-    = label_tag :project_merge_method_merge do
-      = form.radio_button :merge_method, :merge, class: "js-merge-method-radio"
-      %strong Merge commit
-      %br
-      %span.descr
-        A merge commit is created for every merge, and merging is allowed as long as there are no conflicts.
-
-  .radio
-    = label_tag :project_merge_method_ff do
-      = form.radio_button :merge_method, :ff, class: "js-merge-method-radio"
-      %strong Fast-forward merge
-      %br
-      %span.descr
-        No merge commits are created and all merges are fast-forwarded, which means that merging is only allowed if the branch could be fast-forwarded.
-      %br
-      %span.descr
-        When fast-forward merge is not possible, the user must first rebase locally.
-
 .form-group
   .checkbox.builds-feature{ class: ("hidden" if @project && @project.project_feature.send(:builds_access_level) == 0) }
     = form.label :only_allow_merge_if_pipeline_succeeds do

app/views/projects/_merge_request_settings.html.haml

 - form = local_assigns.fetch(:form)
 
+.form-group
+  = label_tag :merge_method_merge, class: 'label-light' do
+    Merge method
+  .radio
+    = label_tag :project_merge_method_merge do
+      = form.radio_button :merge_method, :merge, class: "js-merge-method-radio"
+      %strong Merge commit
+      %br
+      %span.descr
+        A merge commit is created for every merge, and merging is allowed as long as there are no conflicts.
+
+  = render 'merge_request_fast_forward_settings', project: @project, form: form
+
 = render 'projects/merge_request_merge_settings', form: form