Some "concrete" versions on the command line, e.g. `qt@5` are really
meant to satisfy some actual concrete version from a package. We should
only assume the user is introducing a new, unknown version on the CLI
if we, well, don't know of any version that satisfies the user's
request. So, if we know about `5.11.1` and `5.11.3` and they ask for
`5.11.2`, we'd ask the solver to consider `5.11.2` as a solution. If
they just ask for `5`, though, `5.11.1` or `5.11.3` are fine solutions,
as they satisfy `@5`, so use them.
Co-authored-by: Harmen Stoppels <harmenstoppels@gmail.com>
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