Use the parameter 'name' everywhere for consistency

Fix https://github.com/ansible/ansible/issues/11395

system/known_hosts.py

@@ -58,7 +58,7 @@ EXAMPLES = '''
 # Example using with_file to set the system known_hosts file
 - name: tell the host about our servers it might want to ssh to
   known_hosts: path='/etc/ssh/ssh_known_hosts'
-               host='foo.com.invalid'
+               name='foo.com.invalid'
                key="{{ lookup('file', 'pubkeys/foo.com.invalid') }}"
 '''