Document how to disable display templates using UIHintAttribute

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

We can define templates and place them in the *DisplayTemplates* folder. This allows us to automatically use the template for a particular data type. We can also use `UIHintAttribute` to specify which template should be used. But what if we want to disable the template in the *DisplayTempates* folder? Shouldn't `UIHintAttribute` allow us to do this?

I tried `[UIHint(null)]`, `[UIHint("")]`, and `[UIHint("None")]`, but Razor Pages continues to use the template in the *DisplayTemplates* folder!

### Describe the solution you'd like

Give `UIHintAttribute` a way to disable the template in the *DisplayTemplates* folder, and then document it.

### Additional context

I've spent over an hour online trying to find information on this. It should be part of the `UIHintAttribute` documentation.