Use previous message when tail is followed by regular items

Now it's consistent with the way we print other error messages and
allows us greater control, like adding additional extra labels and such.

Now it can tell the difference when a pattern has the wrong arity and
refer to it as a "pattern" instead of a "call".

Added Warning::TopLevelDefinitionShadowsImport with tests and snapshots

This changes the behavior so that `import one/two.three` issues the typical
error, as `one/two` implies the user meant to use Gleam's import syntax,
and likely just made a typo.

Also fixes the whitespace for the error, which was found while examining the snapshot

The `.` is really the problem in this instance, and so it seems better to point to it as the problem as opposed to the identifier

This commit updates the pubgrub and hexpm dependency version. It also
makes sure that version ranges are parsed on creation rather than use to
improve error handling.

So it is consistent with the other "duplicate error" messages by
highlighting the second import as the primary source of the warning