Sources and registries documentation suggestions

[fluffysquirrels]

CC: @ehuss as discussed on discord

These are suggestions only, happy to discuss.

Source replacement:

• Define a "source" on this page, perhaps copying the definition from the glossary.
• There are two blocks of toml near the top of this page that define the configuration for source replacement. Merge these.
• "[P]rivate registry support is planned for a future version of Cargo.": the future is here! Link to the registries documentation.
• Describe when sources are used: when cargo fetches source code for dependencies to build them. Are there other cases? List some of the commands that use sources.
• Add links to cargo-local-registry and cargo-vendor on crates.io

Registries:

• Links to cargo-local-registry EDIT: I don't think local registries are supported by e.g. cargo publish and cargo login, so this is not relevant.

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I'm happy to submit a PR for these. I may have other suggestions as I start to write.

Hope that helps!

[ehuss]

These sound great!

Are there other cases?

Just for dependencies.

Add links to cargo-local-registry and cargo-vendor on crates.io

The source replacement page does link to both of the commands. Maybe because the CSS style for code overrides the a link styling it's hard to see. I believe this is due to rust-lang/mdBook#537.

Thanks! Any help with clarifying and expanding the docs is greatly appreciated!

[fluffysquirrels]

@ehuss, thanks for the clarifications.

Given the mdBook issue hasn't been updated in 6 months, is it worth sidestepping it and rendering the links like:

The primary way to manage and create local registry sources is through the cargo-local-registry subcommand, available as a crate on crates.io, and can be installed with cargo install cargo-local-registry.

I'm working on the other edits.