grep(1) bug - duplicate output lines

From: Jamie Landeg-Jones <jamie_at_catflap.org>
Date: Thu, 28 Sep 2023 02:40:54 UTC 
When using color=always and a regex of '.' (for example), output lines
are duplicated.

$ grep --version
grep (BSD grep, GNU compatible) 2.6.0-FreeBSD

E.G.:

$ grep --color=always . /etc/fstab

Cheers, Jamie