Fix the placeholder in the select form to prevent it from being selected

[sebasttti]

Hello, I found the attribute of placholder in select form fascinating, but sometimes I clicked on it as an option, and, becuase of it is a placeholder, it muest not be clickeable. This probles is fixed easily in html, adding the attribute hidden yo the placeholder option. So I did it in the source code, adn I wanted to share it with you to be applied in the repository