This redirects the output of the cd command to /dev/null so that in cases where CDPATH is set, the output from cd won't be captured. Will not add the redirect on Windows. Fixes #980.
Fixes #980 - Route output of cd to dev/null
In the corner case where CDPATH is used, `cd` outputs the
directory that was `cd`'d to. To keep this output from
messing up commands, redirect output to /dev/null.
don't redirect on windows.
Changelog re #1312