Fix function prototyping in automation scripting editor

To reproduce, start a new automation scripting and in the (new) default editor (which uses Ctrl-Space to autocomplete):

• Enter

  Document.Cre(Ctrl-Space)(Choose Create) 
  

  ==> autocompletes as

  Document.Create
  

  (no function prototype)

• Enter

  Doc(Ctrl-Space)(Choose Document).(Ctrl-Space)(Choose Create)
  

  (mind the "." above!!!)
  ==> autocompletes as:

    Document.Create(
  input, {
  	/*required:true - type: string*/
  	'type': ,
  	/*required:false - type: string*/
  	'name': ,
  	/*required:false - type: properties*/
  	'properties': 
  }
  );
  

  (with function prototype)

Once the function prototyping has worked once, it always work OK until page reloading (hit F5 for instance), when the issue pops up again.