Wrong credit for "clearfix"

[thierryk]

The doc about clearfix says:

Easily clear floats by adding .clearfix to the parent element. Utilizes the micro clearfix as popularized by Nicolas Gallagher. Can also be used as a mixin.

but the clearfix rule in v4 looks like this:

@mixin clearfix() {
  &::after {
    display: block;
    clear: both;
    content: "";
  }
}

which resembles more to the "clearfix" rule from this article on cssmojo.com:

.clearfix:after {
  content: "";
  display: block;
  clear: both;
}