Add core to Cargo workspace

[lf-]

This was breaking completion/IDE support for rust-analyzer in libcore (rust-lang/rust-analyzer#9203). If this is an intentional omission, can we add a comment documenting the reasoning?

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[bjorn3]

It should already automatically have been automatically added to the cargo workspace because the known member std depends on it, it is located within the workspace directory and it isn't explicitly excluded.

https://doc.rust-lang.org/cargo/reference/workspaces.html?highlight=workspace#the-workspace-section

All path dependencies residing in the workspace directory automatically become members. Additional members can be listed with the members key, which should be an array of strings containing directories with Cargo.toml files.

[lf-]

It should already automatically have been automatically added to the cargo workspace because the known member std depends on it, it is located within the workspace directory and it isn't explicitly excluded.

https://doc.rust-lang.org/cargo/reference/workspaces.html?highlight=workspace#the-workspace-section

All path dependencies residing in the workspace directory automatically become members. Additional members can be listed with the members key, which should be an array of strings containing directories with Cargo.toml files.

Ah! This is probably a r-a bug then, and is not on this side then. We should be able to process this case and we aren't doing it yet. I'll just keep this commit around on my end as a workaround until r-a can handle this properly. Closing. Thanks!