Update docsy theme

[LorenzBischof]

I did some light testing and everything seems to work. We can probably merge this and slowly migrate and test the trainings.

[splattner]

Did you remove the "copy" button by intention?

[LorenzBischof]

Yes. That was added in Docsy 0.5.1: google/docsy#1245 You can test the new theme by adding replacements in the hugo-training-template.

[LorenzBischof]

Do you need my help with testing and deploying? If not, feel free to merge.

[splattner]

I merged, do yo mind also updating and testing it in acend/hugo-training-template#302 and acend/hugo-training-template#301 ?
when its fine there, I think I'll be able to apply the necessary changes to all our other repos.

@schlapzz also said in our internal chat

Bei PR301 müsste man wohl die Color Vars anpassen (gray-X) sind im SCSS von Docsy 0.9.1 nicht mehr vorhanden... Wir haben aber in unseren SCSS z.B. docsy-acend) noch diverse Referenzen auf diese Farben. (Siehe hier: https://github.com/acend/docsy-plus/blob/main/assets/scss/site.scss#L33)

[LorenzBischof]

gray-300 is a bootstrap variable. I changed the implementation a bit and it should work again.