rustup: install completions for Cargo.

[gbrlsnchs]

General

• This is a new package and it conforms to the quality requirements

Have the results of the proposed changes been tested?

• I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
• I generally don't use the affected packages but briefly tested this PR

[ericonr]

This makes the rustup package conflict with cargo, which isn't ideal.

[gbrlsnchs]

This makes the rustup package conflict with cargo, which isn't ideal.

Is there a useful use case where one installs both cargo and rustup?

[ericonr]

There can be, I don't think we should make it impossible to install them together...

To be fair, I don't feel this as much because fish has built in completions already, but still.

[gbrlsnchs]

There can be, I don't think we should make it impossible to install them together...

To be fair, I don't feel this as much because fish has built in completions already, but still.

I agree. The reason I opened this PR is because I switched from manually installed rustup to the one packaged by Void, and the first thing I noticed was my Cargo completion wasn't working anymore. What do you think is the best solution for this case? Should I keep my rustup template patched locally only? I wouldn't mind, really.

[ericonr]

I'm really not sure... The final version of this PR, if merged, should also remove installation of these files from the cargo package, but I'm mostly against changing this. There isn't an ideal solution, I think.

[ericonr]

Ok, I'm closing this for now.