[Bug Report] v-data-iterator does not support a loading prop but the docs say it does.

[MatthewAry]

Versions and Environment

Vuetify: 1.4.3
Vue: 2.5.22
Browsers: Chrome 71.0.3578.98
OS: Mac OS 10.14.2

Steps to reproduce

Look at the v-data-iterator API docs and note that it states that there is a loading prop.
Create a v-data-iterator and set the loading prop to true. Note how there is no loading bar.

Expected Behavior

Either the loading prop should work on v-data-iterator OR v-data-iterator should have a progress slot OR the prop described in the API should be removed.

Actual Behavior

Nothing happens when you use the loading prop.

Reproduction Link

https://codepen.io/MatthewAry/pen/RvWKQQ

Other Comments

#4008 An issue was created for this problem previously but was closed by the author before it could be addressed by the team.