Account Move Template: raise UserError in case the format is not valid by keyword

Module: account

Scenario:

User run 'Create Move from Template' wizard, select a template that some keywords are not valid, and click create:

Traceback (most recent call last):
  File "/tryton/trytond/trytond/protocols/dispatcher.py", line 204, in _dispatch
    result = rpc.result(meth(*c_args, **c_kwargs))
                        ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tryton/trytond/trytond/wizard/wizard.py", line 340, in execute
    result = wizard._execute(state_name)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tryton/trytond/trytond/wizard/wizard.py", line 380, in _execute
    result = self._execute(transition())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tryton/trytond/trytond/wizard/wizard.py", line 375, in _execute
    do_result = do(action)
                ^^^^^^^^^^
  File "/tryton/trytond/trytond/modules/account/move_template.py", line 398, in do_open_
    move = self.create_move()
           ^^^^^^^^^^^^^^^^^^
  File "/tryton/trytond/trytond/modules/account/move_template.py", line 373, in create_move
    move = template.get_move(values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/tryton/trytond/trytond/modules/account/move_template.py", line 61, in get_move
    move.description = self.description.format(
                       ^^^^^^^^^^^^^^^^^^^^^^^^
KeyError: 'descAs'

The user don't know of the reason for the traceback.

Version 6.8