Small typo.

I feel bad for sending you these single-character changes. On the plus side, someone is reading your documentation! :)
Corrected default_sort example

The given example was causing a syntax error.
One more correction to default_sort example

On my previous commit, I had fixed the syntax error but completely missed how the sorting syntax actually worked.
Merge pull request #324 from jenmontes/patch-1

Small typo