DM-48395: Document newly added support for Mermaid graphs

[enourbakhsh]

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.15%. Comparing base (769567f) to head (d2afd0a).
Report is 2 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #319   +/-   ##
=======================================
  Coverage   90.15%   90.15%           
=======================================
  Files          50       50           
  Lines        4631     4631           
  Branches      426      426           
=======================================
  Hits         4175     4175           
  Misses        325      325           
  Partials      131      131           

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