Minor junos_config module changes (#23972)

* Minor junos_config module changes

* Add note for json config support
* Add example for lines argument
* Fix future warning for ElementTree

* Remove unwanted space

lib/ansible/modules/network/junos/junos_config.py

@@ -142,6 +142,8 @@ requirements:
 notes:
   - This module requires the netconf system service be enabled on
     the remote device being managed.
+  - Loading JSON-formatted configuration I(json) is supported
+    starting in Junos OS Release 16.1 onwards.
 """
 
 EXAMPLES = """
@@ -151,6 +153,14 @@ EXAMPLES = """
     comment: update config
     provider: "{{ netconf }}"
 
+- name: load configure lines into device
+  junos_config:
+    lines:
+      - set interfaces ge-0/0/1 unit 0 description "Test interface"
+      - set vlans vlan01 description "Test vlan"
+    comment: update config
+    provider: "{{ netconf }}"
+
 - name: rollback the configuration to id 10
   junos_config:
     rollback: 10
@@ -330,7 +340,7 @@ def main():
 
     else:
         diff = configure_device(module, warnings)
-        if diff:
+        if diff is not None:
             if module._diff:
                 result['diff'] = {'prepared': diff}
             result['changed'] = True