Bad ShapeCast / RayCast `enabled` property documentation

### Tested versions

Applies to `ShapeCast*` and `RayCast*` docs, present on **all** versions.
https://docs.godotengine.org/en/latest/classes/class_shapecast3d.html

### System information

N/A (Documentation)

### Issue description

The enabled property of ShapeCast* / RayCast* is wrong:
> If true, collisions will be reported.

This is not true, as using `force_shapecast_update` does not require `enabled` to be set to true.
It should also include that having it enabled results in automatically recomputed data with each _physics_process tick, similar to https://docs.godotengine.org/en/latest/classes/class_shapecast3d.html#class-shapecast3d-method-force-shapecast-update.

### Steps to reproduce

N/A (Documentation)

### Minimal reproduction project (MRP)

N/A (Documentation)

Start with the linked ShapeCast3D class documentation and compare the enabled property with force_shapecast_update. Review the corresponding ShapeCast* and RayCast* documentation entries, then update the explanation so it distinguishes forced updates from automatic physics-tick recomputation. Done means the enabled behavior is accurately documented for both class families.

Written by the indexing model from the issue text.