Better naming etc. in Rust crate about slint

[ogoffart]

Thanks for the suggestion.

I think most of it make sense, and it can indeed be done by adding a new and deprecating the old one. Although i don't think that can be done for trait method

row_data() to row()

Not sure about this one. row() could be mistaken with the row number.

property getters use that prefix. I understand that using no prefix/suffix at all makes name conflicts with other methods possible that generated types may provide. Maybe Slint could use a prop_ prefix instead?

I think it's fine to break the guideline in this case.