New man page added for gmgeantino

New man page was added for gmgeantino, other manpages have slight updates.

added 10 commits

• de89e0dd...cb4e9f72 - 8 commits from branch main
• 14f9ee5c - Add manual page for gmgeantino
• 6fbeb6bc - fixup the gmgeantino man page (remove temporarily deprecated flags)

Compare with previous version

merged