Change ps(1) output width to unlimited if not interactive

[• karels]

Summary

Apply patch submitted with PR 217159 to make ps use unlimited
width when not associated with a terminal (i.e., none of stdout, stdin,
or stderr is a tty). Update comments and man page correspondingly.
This change was requested to work around lack of -ww in scripts from
third-party packages, including Hadoop, and adds a small measure of
Linux compatibility. Hopefully few if any non-interactive scripts
depend on the old default of 79.

Test Plan

tested on head

[vangyzen]

bin/ps/ps.1

107 ↗

(On Diff #40059)

otherwised -> otherwise

[• karels]

Thanks for catching the typo.