Lack of SASS partials support

[AlexWayfer]

Hello!

SASS has partials, which filenames start with _, but it's not written in @import: https://sass-lang.com/documentation/at-rules/import

So, we're having incorrect links (with 404).

Example: https://github.com/nana-4/materia-theme/blob/8988c72/src/chrome/chrome-scrollbar-dark/scrollbars.scss

Incorrect link to https://github.com/nana-4/materia-theme/blob/8988c72/src/_sass/colors.scss

Correct link is https://github.com/nana-4/materia-theme/blob/8988c72/src/_sass/_colors.scss