change: prefer minwidth / minheigth to window size

[amedama41]

Suggestion

Currently, menu or bookmark floating window size is limitted to the parent window size even if minwidth / minheight is specified by configuration such bellow.

    require("vfiler/extensions/menu/config").setup({
        options = {
            floating = {
                minwidth = 100,
            }
        },
   })

By this limitation, the floating window tends to be too narrow on explorer style.
So I want to prefer minwidth / minheigth to the parent window size.

[obaland]

Thank you for your commitment.