Merge pull request #5087 from fantasya-pbem/docs/4946_SSH-restrictions

docs: linked recommended restrictions to ssh public keys on borg servers in faq, fixes #4946

docs/deployment/hosting-repositories.rst

@@ -1,5 +1,6 @@
 .. include:: ../global.rst.inc
 .. highlight:: none
+.. _hosting_repositories:
 
 Hosting repositories
 ====================

docs/faq.rst

@@ -557,6 +557,8 @@ These are your options to protect against that:
 - Mount C's filesystem on another machine and then create a backup of it.
 - Do not give C filesystem-level access to S.
 
+See :ref:`hosting_repositories` for a detailed protection guide.
+
 How can I protect against a hacked backup server?
 -------------------------------------------------