Disable adding a feature when using cargo-add --optional

[passcod]

Problem

With #13071, cargo add started creating explicit features for new optional deps. While I understand the reasoning, this is frustrating to have to keep remembering to delete that line when I actively want to use the newer behaviour that adding optional dependencies doesn't create features.

Proposed Solution

Some kind of opt-in switch or heuristic that will let me disable this behaviour.

Notes

No response

[epage]

In addition to

• Pedagogical purposes
• Jump starting people who want to make the dependency a feature

We did this because it will be an error to do anything else in the next edition, see rust-lang/rfcs#3491

Any switch will be short-lived. Since this use case has the user editing the file either way, I don't think a switch would have been worth it.

However, like #13411, I wonder if we should add a Status message saying that we added the feature. This way users are less likely to miss that it was done.

[passcod]

Your proposed/PR addition seems a fine resolution, I'm gonna go ahead and close this ticket while that lands.