The initial idea is that all the built-in attributes AND user created attributes should show up in a popup when user tries to write an attribute name.
For the built-in attributes, we may only show as active the attributes that are compatible with the node. We may need to visually create a distinction between built-in and user created attributes.
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Results:
{F9750374, size=full}
Categories:
* Built-in - reserved names that can or may exist at some point (`position`, `radius`)
* Nodes - result of the current node treee (`mask`, `proximity`)
* Custom - attributes made elsewhere like UV Maps, Vertex Groups. (`UVMap`, `VCol`)