This optimization doesn't really make a difference and it makes it
harder to separate UI / edit concerns.

This gives a hint to users that we might not be showing the feature list
for the latest version but the earliest version.

Also when using a workspace dependency or re-using an existing
dependency, this is a good reminder of what the version requirement is
that was selected.

However, when the user or add (the common case) selected a full
precision requirement, this is redundant.

I'm also mixed on whether the meta version should show up.

Fixes rust-lang#11073

This will only show the messaeg if we didn't already show a version req
with full precision specified ... mostly.  We'll also skip it if its a
local or git dependency but we never show the version in those cases
because it doesn't matter.

The `precise_version` logic came from cargo-upgrade.