docs: add manual page fro sysc.cfg

docs/config/sync/format.rst

@@ -0,0 +1,15 @@
+Each entry starts with a header ``sync: <name>``, followed by the
+job configuration options.
+
+::
+
+  sync: job1
+	store store1
+	remote-store store1
+	remote lina
+
+  sync: ...
+	
+
+You can use the ``proxmox-backup-manager sync-job`` command to manipulate
+this file.

docs/config/sync/man5.rst

@@ -0,0 +1,35 @@
+==========================
+sync.cfg
+==========================
+
+.. include:: ../../epilog.rst
+
+-------------------------------------------------------------
+Synchronization Job Configuration
+-------------------------------------------------------------
+
+:Author: |AUTHOR|
+:Version: Version |VERSION|
+:Manual section: 5
+
+Description
+===========
+
+The file /etc/proxmox-backup/sync.cfg is a configuration file for
+Proxmox Backup Server. It contains the synchronization job
+configuration.
+
+
+File Format
+===========
+
+.. include:: format.rst
+
+
+Options
+=======
+
+.. include:: config.rst
+
+
+.. include:: ../../pbs-copyright.rst