Suggestion: `fs-dirname` should support non-existing paths

[balupton]

Right now it'll fail if the path does not exist, there are workarounds we can do.

Once achieved, we should replace as many dirname calls with fs-dirname, as dirname has so many issues.

[balupton]

fs-absolute also requires existing paths

[balupton]

fs-dirname is also such a misnomer, it should be fs-parent if that is the intent

10:34:25:/Users/balupton/.local/share/dorothy:master
> dirname .
.
10:43:46:/Users/balupton/.local/share/dorothy:master
> dirname ..
.
10:43:52:/Users/balupton/.local/share/dorothy:master
> dirname $DOROTHY
/Users/balupton/.local/share
10:44:22:/Users/balupton/.local/share/dorothy:master
> dirname commands
.
10:44:29:/Users/balupton/.local/share/dorothy:master
> dirname (pwd)
/Users/balupton/.local/share
10:44:44:/Users/balupton/.local/share/dorothy:master
> dirname non/existent/path
non/existent
10:45:11:/Users/balupton/.local/share/dorothy:master
> dirname non/existent/path/
non/existent
10:45:12:/Users/balupton/.local/share/dorothy:master
> dirname commands/
.
10:45:17:/Users/balupton/.local/share/dorothy:master
> dirname (pwd)/commands/
/Users/balupton/.local/share/dorothy

dirname always returns parent directory, but if any relative path is provided, then it is fine returning .