Removed unused HAML templates

They aren't used in any views as it was swapped over to JSON only on
the controller

app/assets/javascripts/diffs/components/commit_widget.vue

 <script>
 import CommitItem from './commit_item.vue';
 
-/**
- * CommitWidget
- *
- * -----------------------------------------------------------------
- * WARNING: Please keep changes up-to-date with the following files:
- * - `views/projects/merge_requests/diffs/_commit_widget.html.haml`
- * -----------------------------------------------------------------
- *
- * This Component was cloned from a HAML view. For the time being,
- * they coexist, but there is an issue to remove the duplication.
- * https://gitlab.com/gitlab-org/gitlab-foss/issues/51613
- *
- */
 export default {
   components: {
     CommitItem,

app/assets/stylesheets/fontawesome_custom.scss

@@ -88,11 +88,6 @@
   content: '\f078';
 }
 
-.fa-remove::before,
-.fa-times::before {
-  content: '\f00d';
-}
-
 .fa-caret-down::before {
   content: '\f0d7';
 }

app/views/projects/merge_requests/diffs/_commit_widget.html.haml

--#-----------------------------------------------------------------
-  WARNING: Please keep changes up-to-date with the following files:
-  - `assets/javascripts/diffs/components/commit_widget.vue`
--#-----------------------------------------------------------------
-- collapsible = local_assigns.fetch(:collapsible, true)
-
-- if @commit
-  .info-well.mw-100.mx-0
-    .well-segment
-      %ul.blob-commit-info
-        = render 'projects/commits/commit', commit: @commit, merge_request: @merge_request, view_details: true, collapsible: collapsible

app/views/projects/merge_requests/diffs/_different_base.html.haml

-- if @merge_request_diff && different_base?(@start_version, @merge_request_diff)
-  .mr-version-controls
-    .content-block
-      = sprite_icon('information-o')
-      Selected versions have different base commits.
-      Changes will include
-      = link_to project_compare_path(@project, from: @start_version.base_commit_sha, to: @merge_request_diff.base_commit_sha) do
-        new commits
-      from
-      = succeed '.' do
-        %code.ref-name= @merge_request.target_branch

app/views/projects/merge_requests/diffs/_diffs.html.haml

-= render 'projects/merge_requests/diffs/version_controls'
-= render 'projects/merge_requests/diffs/different_base'
-= render 'projects/merge_requests/diffs/not_all_comments_displayed'
-= render 'projects/merge_requests/diffs/commit_widget'
-
-- if @merge_request_diff&.empty?
-  .row.empty-state.nothing-here-block
-    .col-12
-      .svg-content= image_tag 'illustrations/merge_request_changes_empty.svg'
-    .col-12
-      .text-content.text-center
-        %p
-          No changes between
-          %span.ref-name= @merge_request.source_branch
-          and
-          %span.ref-name= @merge_request.target_branch
-          .text-center= link_to 'Create commit', project_new_blob_path(@project, @merge_request.source_branch), class: 'btn btn-success'
-- else
-  - diff_viewable = @merge_request_diff ? @merge_request_diff.viewable? : true
-  - if diff_viewable
-    = render "projects/diffs/diffs", diffs: @diffs, environment: @environment, merge_request: true

app/views/projects/merge_requests/diffs/_not_all_comments_displayed.html.haml

-- if @commit || @start_version || (@merge_request_diff && !@merge_request_diff.latest?)
-  .mr-version-controls
-    .content-block.comments-disabled-notif.clearfix
-      = sprite_icon('information-o')
-      = succeed '.' do
-        - if @commit
-          Only comments from the following commit are shown below
-        - else
-          Not all comments are displayed because you're
-          - if @start_version
-            comparing two versions of the diff
-          - else
-            viewing an old version of the diff
-      .float-right
-        = link_to diffs_project_merge_request_path(@merge_request.project, @merge_request), class: 'btn btn-sm' do
-          Show latest version
-          = "of the diff" if @commit

app/views/projects/merge_requests/diffs/_version_controls.html.haml

-- if @merge_request_diff && @merge_request_diffs.size > 1
-  .mr-version-controls
-    .mr-version-menus-container.content-block
-      Changes between
-      %span.dropdown.inline.mr-version-dropdown
-        %a.dropdown-toggle.btn.btn-default{ data: { toggle: :dropdown, display: 'static' } }
-          %span
-            - if @merge_request_diff.latest?
-              latest version
-            - else
-              version #{version_index(@merge_request_diff)}
-          = icon('caret-down')
-        .dropdown-menu.dropdown-select.dropdown-menu-selectable
-          .dropdown-title
-            %span Version:
-            %button.dropdown-title-button.dropdown-menu-close{ aria: { label: "Close" } }
-              = icon('times', class: 'dropdown-menu-close-icon')
-          .dropdown-content
-            %ul
-              - @merge_request_diffs.each do |merge_request_diff|
-                %li
-                  = link_to merge_request_version_path(@project, @merge_request, merge_request_diff, @start_sha), class: ('is-active' if merge_request_diff == @merge_request_diff) do
-                    %div
-                      %strong
-                        - if merge_request_diff.latest?
-                          latest version
-                        - else
-                          version #{version_index(merge_request_diff)}
-                    %div
-                      %small.commit-sha= short_sha(merge_request_diff.head_commit_sha)
-                    %div
-                      %small
-                        #{number_with_delimiter(merge_request_diff.commits_count)} #{'commit'.pluralize(merge_request_diff.commits_count)},
-                        = time_ago_with_tooltip(merge_request_diff.created_at)
-
-      - if @merge_request_diff.base_commit_sha
-        and
-        %span.dropdown.inline.mr-version-compare-dropdown
-          %a.btn.btn-default.dropdown-toggle{ data: { toggle: :dropdown, display: 'static' } }
-            - if @start_version
-              version #{version_index(@start_version)}
-            - else
-              %span.ref-name= @merge_request.target_branch
-            = icon('caret-down')
-          .dropdown-menu.dropdown-select.dropdown-menu-selectable
-            .dropdown-title
-              %span Compared with:
-              %button.dropdown-title-button.dropdown-menu-close{ aria: { label: "Close" } }
-                = icon('times', class: 'dropdown-menu-close-icon')
-            .dropdown-content
-              %ul
-                - @comparable_diffs.each do |merge_request_diff|
-                  %li
-                    = link_to merge_request_version_path(@project, @merge_request, @merge_request_diff, merge_request_diff.head_commit_sha), class: ('is-active' if merge_request_diff == @start_version) do
-                      %div
-                        %strong
-                          - if merge_request_diff.latest?
-                            latest version
-                          - else
-                            version #{version_index(merge_request_diff)}
-                      %div
-                        %small.commit-sha= short_sha(merge_request_diff.head_commit_sha)
-                      %div
-                        %small
-                          = time_ago_with_tooltip(merge_request_diff.created_at)
-                %li
-                  = link_to merge_request_version_path(@project, @merge_request, @merge_request_diff), class: ('is-active' unless @start_version) do
-                    %div
-                      %strong
-                        %span.ref-name= @merge_request.target_branch
-                        (base)
-                    %div
-                      %strong.commit-sha= short_sha(@merge_request_diff.base_commit_sha)

spec/views/projects/merge_requests/diffs/_diffs.html.haml_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe 'projects/merge_requests/diffs/_diffs.html.haml' do
-  include Devise::Test::ControllerHelpers
-
-  let(:user) { create(:user) }
-  let(:project) { create(:project, :public, :repository) }
-  let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project, author: user) }
-
-  before do
-    allow(view).to receive(:url_for).and_return(controller.request.fullpath)
-
-    assign(:merge_request, merge_request)
-    assign(:environment, merge_request.environments_for(user).last)
-    assign(:diffs, merge_request.diffs)
-    assign(:merge_request_diffs, merge_request.diffs)
-    assign(:diff_notes_disabled, true) # disable note creation
-    assign(:use_legacy_diff_notes, false)
-    assign(:grouped_diff_discussions, {})
-    assign(:notes, [])
-  end
-
-  context 'for a commit' do
-    let(:commit) { merge_request.commits.last }
-
-    before do
-      assign(:commit, commit)
-    end
-
-    it "shows the commit scope" do
-      render
-
-      expect(rendered).to have_content "Only comments from the following commit are shown below"
-    end
-  end
-end