Ansible 2,7 "use_tty" fix

Per Issue #6453, Ansible@2.7 targetting Windows was throwing the following error when setup as the docs instruct:
"Requested option use_tty was not defined in configuration"

This is caused by something in Ansible silently discarding the whole `DOCUMENTATION` string configuration when it can't parse it. The changed line in this PR fixes that. :)

website/source/docs/provisioners/ansible.html.md

@@ -262,8 +262,7 @@ DOCUMENTATION = '''
     connection: packer
     short_description: ssh based connections for powershell via packer
     description:
-        - This connection plugin allows ansible to communicate to the target packer
-        machines via ssh based connections for powershell.
+        - This connection plugin allows ansible to communicate to the target packer machines via ssh based connections for powershell.
     author: Packer
     version_added: na
     options: