[InterNetNews/inn] e79e33: Improve actsync documentation

[Julien ÉLIE]

  Branch: refs/heads/2.6
  Home:   https://github.com/InterNetNews/inn
  Commit: e79e330c68c2ae3be8cc7f29e51b077e177c056a
      https://github.com/InterNetNews/inn/commit/e79e330c68c2ae3be8cc7f29e51b077e177c056a
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2022-02-05 (Sat, 05 Feb 2022)

  Changed paths:
    M doc/pod/actsync.pod

  Log Message:
  -----------
  Improve actsync documentation

Add a new section at the beginning to summarize how to use actsyncd.

Document that debug-level option is not possible for FTP retrieval.

Change news.uu.net to news.server.com out of clarity.  There's no official
news server to synchronize from.