Document rust's (hard-to-search) sigils, characters, and symbols in one appendix

[mrhota]

This idea is inspired by Clojure's "weird characters" guide. They grouped all of Clojure's hard-to-search symbols into one page for easy reference.

Given that Rust has tons of sigils and symbols itself, and that such an easily searchable guide would be invaluable, is the reference the place for it? Does such a thing already exist?

[Havvy]

Exists in the first book: https://doc.rust-lang.org/book/first-edition/syntax-index.html

[Havvy]

The second book has two appendices that assume the role of that index, so when we fully deprecate the first book, that /would/ be a regression in documentation. It is referency material, so I don't see why we couldn't pull it in.

cc @steveklabnik for opinions?

[QuietMisdreavus]

I'm in favor of migrating the syntax index to the reference, since we've salvaged other items from book1 that didn't have an equivalent in book2 (specifically the FFI section).

[steveklabnik]

Yeah, seems fine.

[alercah]

I'd be happy to take this on.

[Havvy]

Go for it. It'd basically be copying the appendix from the first book, and possibly updating it for anything that's been missed for awhile.

[alercah]

I unfortunately lost my WIP on this, and don't have the energy to start it again soon, so I'm reopening this for anyone to claim.