Fix typos in application.scss

app/assets/stylesheets/application.scss

@@ -13,9 +13,9 @@
 
 /*
  * Welcome to GitLab css!
- * If you need to add or modify UI component that is commont for many pages
- * like table or typography then make changes in framework/ directory.
- * If you need to add uniq style that should affect only one page - use pages/
+ * If you need to add or modify UI component that is common for many pages
+ * like a table or typography then make changes in the framework/ directory.
+ * If you need to add unique style that should affect only one page - use pages/
  * directory.
  */