Replace Recommonmark by MyST

[pablo-de-andres]

Recommonmark is deprecated and no longer recommended by Sphinx. It should be replaced by MyST.

• requirements.txt
• docs/docs/source/conf.py (extensions). See DSMS docs
• Admonitions
• eval_rst directive
• Update: Check for directives inside admonitions

Getting started guide from MyST

[pablo-de-andres]

/cib

[create-issue-branch]

Branch 184-Replace_Recommonmark_by_MyST created!

[kysrpex]

I spotted a bug in https://simphony.readthedocs.io/en/dev/contribute.html, probably due to this change.

[pablo-de-andres]

/cib

[create-issue-branch]

Branch 184-Replace_Recommonmark_by_MyST created!