mermaird graph not rendered in the user documentation section

Summary

graph (mermaid I believe) is not rendered help (for instance gitlab.dom.tld/help/user/project/merge_requests/methods/index.md).

Steps to reproduce

go to https://gitlab.dom.tld/help/user/project/merge_requests/methods/index.md see graphes are not rendered

this is not a browser issue, because I can see rendered on a random public gitlat instance found on internet like https://repository.prace-ri.eu/git/help/user/project/merge_requests/methods/index.md

Example Project

n/a

What is the current bug behavior?

mermaid graphes not rendered

What is the expected correct behavior?

mermaid graphes rendered

Relevant logs and/or screenshots

Results of GitLab environment info

System information
System:         Ubuntu 18.04
Proxy:          no
Current User:   git
Using RVM:      no
Ruby Version:   2.7.7p221
Gem Version:    3.1.6
Bundler Version:2.3.15
Rake Version:   13.0.6
Redis Version:  6.2.8
Sidekiq Version:6.5.7
Go Version:     unknown

GitLab information
Version:        15.8.0-ee
Revision:       1d89c23c9f9
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     PostgreSQL
DB Version:     12.12
URL:            https://gitlab.host.com
HTTP Clone URL: https://gitlab.host.com/some-group/some-project.git
SSH Clone URL:  git@gitlab.host.com:some-group/some-project.git
Elasticsearch:  no
Geo:            no
Using LDAP:     no
Using Omniauth: yes
Omniauth Providers: google_oauth2

GitLab Shell
Version:        14.15.0
Repository storages:
- default:      unix:/var/opt/gitlab/gitaly/gitaly.socket
GitLab Shell path:              /opt/gitlab/embedded/service/gitlab-shell

Results of GitLab application Check

root@gitlab:~# sudo gitlab-rake gitlab:check SANITIZE=true
Checking GitLab subtasks ...

Checking GitLab Shell ...

GitLab Shell: ... GitLab Shell version >= 14.15.0 ? ... OK (14.15.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful

Checking GitLab Shell ... Finished

Checking Gitaly ...

Gitaly: ... default ... OK

Checking Gitaly ... Finished

Checking Sidekiq ...

Sidekiq: ... Running? ... yes
Number of Sidekiq processes (cluster/worker) ... 1/1

Checking Sidekiq ... Finished

Checking Incoming Email ...

Incoming Email: ... Reply by email is disabled in config/gitlab.yml

Checking Incoming Email ... Finished

Checking LDAP ...

LDAP: ... LDAP is disabled in config/gitlab.yml

Checking LDAP ... Finished

Checking GitLab App ...

Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Cable config exists? ... yes
Resque config exists? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Systemd unit files or init script exist? ... skipped (omnibus-gitlab has neither init script nor systemd units)
Systemd unit files or init script up-to-date? ... skipped (omnibus-gitlab has neither init script nor systemd units)
Projects have namespace: ...
2/1 ... yes
3/2 ... yes
3/11 ... yes
42/12 ... yes
42/23 ... yes
49/24 ... yes
42/26 ... yes
42/27 ... yes
42/28 ... yes
42/29 ... yes
42/30 ... yes
42/32 ... yes
42/33 ... yes
42/34 ... yes
42/35 ... yes
42/36 ... yes
42/37 ... yes
42/39 ... yes
42/40 ... yes
42/41 ... yes
42/42 ... yes
42/43 ... yes
15/44 ... yes
42/46 ... yes
3/47 ... yes
3/48 ... yes
41/50 ... yes
42/52 ... yes
42/62 ... yes
5/64 ... yes
3/67 ... yes
5/68 ... yes
42/69 ... yes
42/71 ... yes
5/73 ... yes
42/75 ... yes
42/76 ... yes
42/77 ... yes
42/81 ... yes
42/82 ... yes
Redis version >= 6.0.0? ... yes
Ruby version >= 2.7.2 ? ... yes (2.7.7)
Git user has default SSH configuration? ... yes
Active users: ... 17
Is authorized keys file accessible? ... yes
GitLab configured to store new projects in hashed storage? ... yes
All projects are in hashed storage? ... yes
Elasticsearch version 7.x-8.x or OpenSearch version 1.x ... skipped (Advanced Search is disabled)
All migrations must be finished before doing a major upgrade ... skipped (Advanced Search is disabled)

Checking GitLab App ... Finished


Checking GitLab subtasks ... Finished

Possible fixes

don't know