inim doesn't catch out of bound error
```
inim
INim 0.2.5
Nim Compiler Version 0.18.1 [MacOSX: amd64] at /Users/timothee/.nimble/bin/nim
>>> import sequtils, os
>>> echo toSeq(parentDirs("/a/b"))
@["/a/b", "/a", ""]
>>> let a=toSeq(parentDirs("/a/b"))
>>> a
@["/a/b", "/a", ""] : seq[string]
>>> a[0]
/a/b : string
>>> a[1]
/a : string
>>> a[-1]
@["/a/b", "/a", ""]
>>>

```
the last entry is shown in red  (as is the case for errors), but should show the error instead of returning non-sensical `@["/a/b", "/a", ""]`