Saving markdown page without editing content throws error #2741

Hi,

at the moment if you have a new site in bookstack (markdown) and it is empty like that:

And users try to safe it there comes an error message:

I think it would be nice to have an error message like that:

The reason is, that this is easier to support. I had often the problem that users say "OMG I got this error, broke I bookstack ?"