Documentation: remove old part and add MPIX section#77

Merged

marcjoos-cea merged 2 commits intocea-hpc:masterfrom adrien-cotte:master

Feb 26, 2024

+19-45

Commits on Feb 7, 2024

[doc](user_guide.rst): remove specific TGCC section
adrien-cotte
committed

Commits on Feb 8, 2024

[doc](limitations.rst): Add MPIX_* as a known limitation
adrien-cotte
committed