Added hint to corresponding Wiki page

Author: IzzySoft

doc/config.sample

@@ -3,6 +3,8 @@
 # To override them, copy this file to "config" and adjust it to your needs.
 # Of course you can ommit (remove/comment out) settings which do not differ from yours
 # (e.g. have your "config" file only holding the DEVICE_IP)
+# For a detailed description, please refer to the corresponding Wiki page:
+# https://github.com/IzzySoft/Adebar/wiki/Configuration
 
 # ------------------------=[ directories ]=--
 # base below which all output (scripts and real backups) are placed