fix description of hw-groups config option

Job-configuration.md

@@ -181,8 +181,8 @@ in the job config file.
 	  (API will fill)
 	- _log_ -- default is false, can be omitted, determines whether job
 	  execution will be logged into one shared log file
-	- **hw-groups** -- list of hardware groups for which are specified limits in
-	  this configuration, multiple values separated by `|` symbol
+	- **hw-groups** -- a list of hardware groups for which there are limits
+	  specified in this configuration
 - **tasks** -- list (not map) of individual tasks
 	- **task-id** -- unique identifier of the task in scope of one submission
 	- _priority_ -- higher number, higher priority, defaults to 1