Update documentation for juniper_junos_config for model option

[rsmekala]

Issue Type

• Documentation Report

Module Name

juniper_junos_config

Juniper.Junos role and Python libraries version

Juniper.junos 2.2.1

Summary

Code has been merged for adding model option, but the relevant document has not been updated.

Code merged via #429. @dineshbaburam91 Can you please take this up ??

[rahkumar651991]

merged in collection. closing it.