"cabal list-bin" should list all available targets on failure

**Describe the bug**
`cabal list-bin` returns an error instead of listing all of the available binaries. 

**To Reproduce**
Steps to reproduce the behavior:

```
$ cabal list-bin
```

**Expected behavior**
Similarly to `ls`, I'd expect to see all the binaries. 

E.g., `ls <file>` lists one specified file, but `ls` lists the entire contents of the current directory.