Create tags for all crates?

[newpavlov]

Right now we mostly use the pattern of naming issues as <crate name>: <issue description>. It works fine, but makes harder to filter and search issues about a certain crate. In some repositories we have tags for crates (e.g. in block-ciphers we have aes), but it's more of an exception.

I wonder if we should be more consistent here by creating a tag for each crate in our repositories, and mark all (open) issues with relevant tags. We also probably need to introduce a prefix for such tags.

We also use may the tags for PRs, but I think we should continue to use the naming pattern, since github tags are not represented in Git history.

[tarcieri]

This exists in some repos like https://github.com/RustCrypto/traits/

However, I certainly don't remember to tag everything. It sure would be nice if it were automated in some way.