fio: add job file example (#8567)

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>

pages/common/fio.md

@@ -15,3 +15,7 @@
 - Test random read/write:
 
 `sudo fio --filename={{path/to/file}} --size=500GB --direct=1 --rw=randrw --bs=4k --ioengine=libaio --iodepth=256 --runtime=120 --numjobs=4 --time_based --group_reporting --name={{job_name}} --eta-newline=1`
+
+- Test with parameters from a job file:
+
+`sudo fio {{path/to/job_file}}`