cargo-tree: Change dedupe indicator.

[ehuss]

cargo-tree marks de-duplicated packages with (*). I think that might be a little confusing, and hard-to-discover the meaning. I'd like to propose changing it to be more like npm which uses the word deduped (with the ESC [90m "bright black" color so that it is de-emphasized). Another extension mentioned at #8062 (comment) is to say (deduped from line 13) which could be useful!

[epage]

#15242 introduces color to cargo tree. The way its done though is it relies on the colors being removed at a later stage if --color never. If we'd want the expanded form to only show up with colors, it would take extra steps.

I worry even with dimmed or bright-black, this will be noisy. I wish there was a good unicode character for this. I was hoping for "right and up arrow" but the only one I found starts at the bottom, rather than middle. ... is another possibility.

[weihanglo]

@joshtriplett suggests changing from (*) to somemthing like (already shown) in #15642 (comment).

The other comments in #15642 suggests adding a footnote about (*) to make the meaning clear.

[epage]

In addition to npm's deduped, I wonder how others deal with this.

Granted, one way to deal with the "noise" concern is if we take a lesson out of git's book and had .cargo/config.toml fields for disabling messages we report to the user so they can explicitly acknowledge that they understand them. That is helped when there is a command they can run to do it. I believe this has come up elsewhere but unsure where.