V5 bootstrap@5.3.0-alpha1: Add default border-bottom to dropdown-item

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

.dropdown-menu {
  > .dropdown-item:not(:last-child),
  > li:not(:last-child) .dropdown-item {
    border-bottom: var(--#{$prefix}dropdown-border-width) solid
      var(--#{$prefix}dropdown-border-color);

    &:hover,
    &:focus {
      border-bottom-color: var(--#{$prefix}dropdown-link-hover-bg);
    }

    &:active,
    &:active {
      border-bottom-color: var(--#{$prefix}dropdown-link-active-bg);
    }
  }
}

Motivation and context