Fix passing dir to CLI

[cherniavskii]

I tried to make it work with *, but no success. Looks like sander doesn't support such syntax

[trusktr]

@cherniavskii Hi, actually that * syntax will be expanded by your shell (at least most shells do).

F.e. if you write

ls src/*.js

the sh, bash, or zsh shells will actually run it as if you typed:

ls src/one.js src/two.js src/three.js src/etc.js

for however many files are inside the src folder.

It'd be nice to add folder usage to the docs though.