I changed the document of win_hostname.py. (#43761)

* Host name is contrary to naming convention

<!--- Your description here -->

+label: docsite_pr

* removed yaml separators

lib/ansible/modules/windows/win_hostname.py

@@ -12,7 +12,6 @@ ANSIBLE_METADATA = {'metadata_version': '1.1',
                     'supported_by': 'community'}
 
 DOCUMENTATION = r'''
----
 module: win_hostname
 version_added: "2.6"
 short_description: Manages local Windows computer name.
@@ -29,9 +28,14 @@ author:
 '''
 
 EXAMPLES = r'''
-- name: Change the hostname to new_hostname
+- name: Change the hostname to sample-hostname
   win_hostname:
-    name: new_hostname
+    name: sample-hostname
+  register: res
+
+- name: Reboot
+  win_reboot:
+  when: res.reboot_required
 '''
 
 RETURN = r'''