message: remove fromCSS after merge
diff: @@ -270,7 +270,7 @@ describe('Stylesheet', function () {
  });
  it('with -st-mixin with params with spaces between', function () {
  - const sheet = Stylesheet.fromCSS(`
  + const sheet = fromCSS(`
  :import("./path/to/mixin"){
  -st-named: MyMixin1;
  }
  @@ -287,7 +287,7 @@ describe('Stylesheet', function () {
  });
  it('with -st-mixin with missing params should remove the last', function () {
  - const sheet = Stylesheet.fromCSS(`
  + const sheet = fromCSS(`
  :import("./path/to/mixin"){
  -st-named: MyMixin1;
  }
  @@ -304,7 +304,7 @@ describe('Stylesheet', function () {
  });
  it('with -st-mixin with params normalized', function () {
  - const sheet = Stylesheet.fromCSS(`
  + const sheet = fromCSS(`
  :import("./path/to/mixin"){
  -st-named: MyMixin1;
  }
  @@ -322,7 +322,7 @@ describe('Stylesheet', function () {
  it.skip("not working mixin arguments", function() {
  // postcss-safe-parser outputs wrong AST and it breaks in -st-mixin value parser
  - const sheet = Stylesheet.fromCSS(`
  + const sheet = fromCSS(`
  :import("./path/to/mixin"){
  -st-named: MyMixin1;
  }
  