bulma (file, components): fix color fo icons: icons have no color specified anymore for a while, and use the color of parent elements. As they are often used in a `<a>` element (to work without javascript), they are often using a link color. This commit change a few icons to use a dark color instead.

.list-item-closed {
    text-decoration: line-through #dd0000 0.3em;
    color: hsl(0, 0%, 48%);
}

.status_closed>.title, .list-item.status_closed .xmlui_field__title {
    text-decoration: line-through #000 0.2em;
    color: hsl(0, 0%, 48%);
}