devel/ruby-gems: Update to 3.5.6

While here, mark textproc/rubygem-nokogumbo as BROKEN because build
fails with clean latest ports tree and all supported ruby versions.

ChangeLog:	https://github.com/rubygems/rubygems/blob/v3.5.6/CHANGELOG.md
PR:		276884
Approved by:	sunpoet (ruby@, maintainer)
Exp-run by:	antoine