Associate Rakefile with Ruby icon in diffs

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52654

app/assets/javascripts/vue_shared/components/file_icon/file_icon_map.js

@@ -549,6 +549,7 @@ const fileNameIcons = {
   jenkinsfile: 'jenkins',
   'firebase.json': 'firebase',
   '.firebaserc': 'firebase',
+  Rakefile: 'ruby',
   'rollup.config.js': 'rollup',
   'rollup.config.ts': 'rollup',
   'rollup-config.js': 'rollup',
@@ -583,7 +584,5 @@ const fileNameIcons = {
 };
 
 export default function getIconForFile(name) {
-  return fileNameIcons[name] ||
-         fileExtensionIcons[name ? name.split('.').pop() : ''] ||
-         '';
+  return fileNameIcons[name] || fileExtensionIcons[name ? name.split('.').pop() : ''] || '';
 }

changelogs/unreleased/sh-associate-rakefile-ruby.yml

@@ -0,0 +1,5 @@
+---
+title: Associate Rakefile with Ruby icon in diffs
+merge_request:
+author:
+type: other