I will preface this with that I'm a very new member of the Rust community.
I have read most of the learner's book and skimmed several others such as by example, the 'nomicon, the linked lists book and design patterns and noticed a consistent theme and style to them. I've noticed that there is a menu to select between 5 themes in these books, and the generated docs only allow 3 and sadly my favorite theme "rust" isn't among them.
I will also add that I would like to contribute to this community and would be willing to submit the pull request myself if and when I am familiar enough to do so, and would appreciate any guidance given in this area.
The short version, themes "rust" and "coal" are missing from docs