Disabled nav link with pointer-events

Created by: melih

bootstrap/scss/_navbar.scss is providing only color property for disabled nav links. When there is an href attribute, HTML keeps the tag inactive "as visual" but keeps it active and clickable "as functional".

  .navbar-nav {
    .nav-link {
      color: $navbar-light-color;

      @include hover-focus {
        color: $navbar-light-hover-color;
      }

      &.disabled {
        color: $navbar-light-disabled-color;
      }
    }

To make these lines more useful and meaningful, pointer-events property should also be added so the link with disabled class would really be inactive .

      &.disabled {
        color: $navbar-light-disabled-color;
        pointer-events: none;
      }