tabs: a hacky version of tabs appeared in 1st edition Unix

First edition Unix had an /etc/tabs file. It contained the escape
sequences to set tabs to every 8 stops on an old Teletype Model 37 and
compatible terminals. One would 'cat /etc/tabs' to reset them. Unix at
the time effectively mandated this because the delays in the tty driver
assumed this and tabs didn't work when they were too different from '8'.
Document this historical niggle in HISTORY after it was brought to my
attention on a Hacker News thread.

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