Setting 'Specular Transmission' to a value higher than 0.0 on a standard material (or ext material) -> it wont write to depth buffer

## How can Bevy's documentation be improved?

Provide a link to the documentation and describe how it could be improved. In what ways is it incomplete, incorrect, or misleading?

**Setting 'Specular Transmission' to a value higher than 0.0 on a standard material (or ext material) -> it wont write to depth buffer**

If you have suggestions on exactly what the new docs should say, feel free to include them here. Or alternatively, make the changes yourself and [create a pull request](https://bevyengine.org/learn/book/contributing/code/) instead.

Perhaps here,

https://docs.rs/bevy/latest/bevy/prelude/struct.StandardMaterial.html#structfield.perceptual_roughness

Add notes on these properties in very clear warnings that certain properties , when set above 0.0, will cause the material to not write to the depth buffer. I was shocked to learn that a float is acting like a boolean in this sense esp since checking a float for == 0.0 is not a common pattern in computer science in general.

Start with the StandardMaterial documentation at the linked docs.rs page and review the description of specular transmission and the referenced material properties. Confirm which values affect depth-buffer writing, then update the relevant documentation with clear warnings and verify that the stated behavior matches the material implementation.

Written by the indexing model from the issue text.