chore: remove category field from material_type_enum

[XAMPPRocky]

This change makes so the casing for the category value is consistent between material_type_enum and main_fields. Also okay with changing it so main_fields is uppercase instead but I think this makes the most sense.

[CZDanol]

Hello and thanks for your contribution :)

Hmm, there's nothing wrong with your PR, but material_type has been changed to a FFF-only field, so having the category field there does not make sense at this point.

I don't mind approving this, just thinking whether it would be better to remove the field altogether now.

[XAMPPRocky]

Hmm, there's nothing wrong with your PR, but material_type has been changed to a FFF-only field, so having the category field there does not make sense at this point.

That is actually even better for me, as I was just about to make an issue about how currently the category is overloaded where tags_enum and material_type_enum both use category but they have two conflicting definitions of categories, making it harder to parse.

I'll make a follow up removing it.

[CZDanol]

LGTM, thanks :) Feel free to merge

[XAMPPRocky]

I can't merge? I don't have write permission to the repo 😄

[CZDanol]

Oh, sorry :D