fix links

established (too) late in 2024 but aims at outlining major events that

happened during the year:

 - tpo/tpa%"legacy Git infrastructure retirement (TPA-RFC-36)":

 - [legacy Git infrastructure retirement (TPA-RFC-36)](https://gitlab.torproject.org/groups/tpo/tpa/-/milestones/11#tab-issues):

   repositories have been massively migrated to GitLab's

   [legacy/gitolite namespace](https://gitlab.torproject.org/legacy/gitolite)

 - tpo/tpa%"Debian 12 bookworm upgrade": currently incomplete (12

 - [Debian 12 bookworm upgrade](https://gitlab.torproject.org/groups/tpo/tpa/-/milestones/6): currently incomplete (12

   hosts left or about 13% of the fleet), but hoping to complete

   before the end of 2024

 - work started on upgrading the legacy mail server and improving

   deliverability of mail forwards (tpo/tpa%"TPA-RFC-71: emergency

   email deployments, phase B")

 - includes a major upgrade from Mailman 2 to Mailman 3

   deliverability of mail forwards ([TPA-RFC-71: emergency

   email deployments, phase B](https://gitlab.torproject.org/groups/tpo/tpa/-/milestones/16#tab-issues))

 - includes a [major upgrade from Mailman 2 to Mailman 3](https://gitlab.torproject.org/tpo/tpa/team/-/issues/40471)

 - Improved by 66% build performance on Lektor websites with i18n

   (https://gitlab.torproject.org/tpo/web/lego/-/issues/30)

 - Retired Nagios in favor of a Prometheus-based alerting setup, with

   less noises, faster detection, and better coverage

   (tpo/tpa%"TPA-RFC-33-A: emergency Icinga retirement")

   ([TPA-RFC-33-A: emergency Icinga retirement](https://gitlab.torproject.org/groups/tpo/tpa/-/milestones/13#tab-issues))

 - Started merge with Tails! Some services were retired or merged

   already, but we're mostly at the planning stage, see

   https://gitlab.torproject.org/tpo/tpa/team/-/issues/41721