UDA are not covered in documentation and tour

[Joakim]

On Tuesday, 19 June 2018 at 11:57:47 UTC, Fra Mecca wrote:
> For the past few days I have been eager to understand more 
> about UDA and the only useful links I found are an old 
> discussion about implementation by Walter and this:
> http://ddili.org/ders/d.en/uda.html
> by Ali Çehreli that definitely does the work of explaining it 
> all.
>
> I think we should add a section to the documentation. Is it 
> overkill to include them in the Tour?

They are mentioned in the spec and the tour:

https://dlang.org/spec/attribute.html#uda
https://tour.dlang.org/tour/en/gems/attributes

> Or am I wrong and UDA are already covered somewhere in this 
> site?

Feel free to submit pull requests to add more info to either of 
those locations:

https://github.com/dlang/dlang.org
https://github.com/dlang-tour/english