Merge pull request #980 from arikorn/fix_spurious_scss_deprecation_warnings

fix: spurious deprecation warnings in SCSS code

Author: mrholek

scss/_mixins.scss

@@ -25,8 +25,6 @@
 @forward "mixins/utilities";
 
 // Components
-@forward "mixins/alert";
-@forward "mixins/avatar";
 @forward "mixins/backdrop";
 @forward "mixins/buttons";
 @forward "mixins/caret";