Please add a "Back to top" button on https://www.mql5.com/en/docs website

[DevDengChao]

If I want to go back to the menu/manifest of current section when I'm in the mid of a long document, I have to scroll the long way upside to find the entry.

I'd like to suggest website maintainers to add a fixed "Back to top" button on the right bottom of the viewport in https://www.mql5.com/en/docs .