content: Misleading content on .ion-display-* classes

### URL

https://ionicframework.com/docs/layout/css-utilities#deprecated-classes

### Issue Description

The v8 documentation states that the `.ion-hide-*` classes are now deprecated and will be removed. It also mentions that the `.ion-display-*` classes are recommended to be used instead. It fails to mention that the `.ion-display-*` classes were only introduced in the latest minor version (8.7.0).