Re: [PATCH v6] help: colorize man pages

> We already colorize tools traditionally not colorized by default, like
> diff and grep. Let's do the same for man.
>
> Our man pages don't contain many useful colors (just blue links),
> moreover, many people have groff SGR disabled, so they don't see any
> colors with man pages.
>
> We can set LESS_TERMCAP variables to render bold and underlined text
> with colors in the pager; a common trick[1].
>
> Bold is rendered as red, underlined as blue, and standout (prompt and
> highlighted search) as inverse cyan.
>
> Obviously this only works when the less pager is used.
>
> If the user already has LESS_TERMCAP variables set in his/her
> environment, those are respected and nothing changes.
>
> A new color configuration is added: `color.man` for the people that want
> to turn this feature off, otherwise `color.ui` is respected.
> Additionally, if color.pager is not enabled, this is disregarded.
>
> Normally check_auto_color() would check the value of `color.pager`, but
> in this particular case it's not git the one executing the pager, but
> man. Therefore we need to check pager_use_color ourselves.
>
> Also--unlike other color.* configurations--color.man=always does not
> make any sense here; `git help` is always run for a tty (it would be very
> strange for a user to do `git help $page > output`, but in fact, that
> works anyway, we don't even need to check if stdout is a tty, but just
> to be consistent we do). So it's simply a boolean in our case.
>
> So, in order for this change to have any effect:
>
>  1. The user must use less
>  2. Not have the same LESS_TERMCAP variables set
>  3. Have color.ui enabled
>  4. Not have color.pager disabled
>  5. Not have color.man disabled
>  7. Not have git with stdout directed to a file
>
> Fortunately the vast majority of our users meet all of the above, and
> anybody who doesn't would not be affected negatively (plus very likely
> comprises a very tiny minority).
>
> [1] https://unix.stackexchange.com/questions/119/colors-in-man-pages/147
>
> Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> Phillip Wood <phillip.wood123@gmail.com>
> Comments-by: Jeff King <peff@peff.net>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---