docs-bug(button): Change icon button size missing

[perotom]

Documentation Feedback

There is only an example to change some colours of a button (https://material.angular.io/components/button/styling) but no example of changing the size.
Especially for icon buttons, different sizes are often needed. Right now we are using something like that:

.mdc-icon-button.small {
  line-height: 18px;
  .mat-icon {
    width: 18px;
    height: 18px;
    font-size: 18px;
  }
}

which is probably not the preferred way. I also tried it with:

.small {
  @include mat.icon-button-overrides((
    icon-size: 18px
  ));
}

which doesn't work as expected.

Affected documentation page

https://material.angular.io/components/button/styling