Merge branch 'sh-fix-issue-321771' into 'master'

[RUN ALL RSPEC] Fix spec failure in  spec/features/markdown/markdown_spec.rb

See merge request gitlab-org/gitlab!54410

lib/gitlab/kroki.rb

@@ -13,9 +13,8 @@ module Gitlab
         packetdiag
         rackdiag
       ].freeze
-    DIAGRAMS_FORMATS = ::AsciidoctorExtensions::Kroki::SUPPORTED_DIAGRAM_NAMES
-    DIAGRAMS_FORMATS_WO_PLANTUML = DIAGRAMS_FORMATS
-                                        .reject { |diagram_type| diagram_type == 'plantuml' }
+    DIAGRAMS_FORMATS = (::AsciidoctorExtensions::Kroki::SUPPORTED_DIAGRAM_NAMES - %w(mermaid)).freeze
+    DIAGRAMS_FORMATS_WO_PLANTUML = (DIAGRAMS_FORMATS - %w(plantuml)).freeze
 
     # Get the list of diagram formats that are currently enabled
     #