message: fix(aio): style sidenav-content scrollbar similar to other scrollbars
diff: -body::-webkit-scrollbar, md-sidenav.sidenav::-webkit-scrollbar {
  +body::-webkit-scrollbar, md-sidenav.sidenav::-webkit-scrollbar, .mat-sidenav-content::-webkit-scrollbar {
  + height: 6px;
  width: 6px;
  }
  -body::-webkit-scrollbar-track, md-sidenav.sidenav::-webkit-scrollbar-trac {
  +body::-webkit-scrollbar-track, md-sidenav.sidenav::-webkit-scrollbar-trac, .mat-sidenav-content::-webkit-scrollbar-trac {
  -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.3);
  }
  -body::-webkit-scrollbar-thumb, md-sidenav.sidenav::-webkit-scrollbar-thumb {
  +body::-webkit-scrollbar-thumb, md-sidenav.sidenav::-webkit-scrollbar-thumb, .mat-sidenav-content::-webkit-scrollbar-thumb {
  background-color: $mediumgray;
  outline: 1px solid $darkgray;
  }
  .search-results::-webkit-scrollbar {
  + height: 4px;
  width: 4px;
  }
  