fix(resolver): In errors, show rejected versions over alt versions (#…

…14923)

### What does this PR try to resolve?

The user likely intended what they said and we should tell them why it
didn't work.
Rejected versions also imply alt versions below them.

Fixes #4260

In changing the errors from alt-versions to rejected-versions, I found
part of the old error message was better and changed the message
introduced in #14897 from matching alt-names to alt-versions.

This includes the test for #14921. The "fix" was done before this
because as it was part of the refactors in prep for this.

### How should we test and review this PR?

### Additional information

Next steps after this are to still produce an
`IndexSummary::Unsupported` even if there are deserialization errors, so
long as we know the name and version which should take care of #10623
and #14894.