Replace default value in url by placeholder
Replace default value in url by placeholder

Current browser display a warning if no valid url is entered into the url field of a form.
Here this happens as well if create a news entry, but do not specify an url at all.
This is avoided by using the "placeholder" attribute instead of the "value" attribute.

thorsten/phpMyFAQ,thorsten/phpMyFAQ,thorsten/phpMyFAQ,thorsten/phpMyFAQ