Clarify documentation about performance bar

doc/administration/monitoring/performance/performance_bar.md

@@ -5,17 +5,17 @@ activated, it looks as follows:
 
 ![Performance Bar](img/performance_bar.png)
 
-It allows you to:
+It allows you to see (from left to right):
 
-- see the current host serving the page
-- see the timing of the page (backend, frontend)
-- the number of DB queries, the time it took, and the detail of these queries
+- the current host serving the page
+- the timing of the page (backend, frontend)
+- time taken and number of DB queries, click through for details of these queries
 ![SQL profiling using the Performance Bar](img/performance_bar_sql_queries.png)
-- the number of calls to Redis, and the time it took
-- the number of background jobs created by Sidekiq, and the time it took
-- the number of Ruby GC calls, and the time it took
-- profile the code used to generate the page, line by line
+- time taken and number of calls to Redis
+- time taken and number of background jobs created by Sidekiq
+- profile of the code used to generate the page, line by line for either _all_, _app & lib_ , or _views_. In the profile view, the numbers in the left panel represent wall time, cpu time, and number of calls (based on [rblineprof](https://github.com/tmm1/rblineprof)).
 ![Line profiling using the Performance Bar](img/performance_bar_line_profiling.png)
+- time taken and number of Ruby GC calls
 
 ## Enable the Performance Bar via the Admin panel