Unused dependency checker reports actual rule instead of alias

With the unused dependency checker, currently if there is an alias, the alias's target is printed in the error message instead. That is, in the following

```
scala_library(
name = "a",
srcs = ["A.scala"],
deps = [":b2"],
)

alias(
name = "b2",
actual = ":b"
)

scala_library(
name = "b",
srcs = ["B.scala"]
)
```

the error is

```
ERROR: XXX/bazel_play/BUILD.bazel:4:1: scala //:a failed (Exit 1)
error: Target '//:b' is specified as a dependency to //:a but isn't used, please remove it from the deps.
You can use the following buildozer command:
buildozer 'remove deps //:b' //:a
one error found
one error found
```

As opposed to complaining about ":b2".

This breaks buildozer as well as making it confusing for people.

Reproduce the unused dependency checker behavior with the BUILD.bazel example in the issue, then trace how the checker reports an aliased dependency and generates the buildozer command. Done means the diagnostic and suggested removal command name :b2, the declared alias, rather than :b, its target.

Written by the indexing model from the issue text.