Re: [RFC PATCH 1/3] usage: extract `prefix_suffix_lines()` from `advise()`

> advice.c contains a useful code snippet which takes a multi-line string
> and prints the lines, prefixing and suffixing each line with two
> constant strings. This was originally added in 23cb5bf3b3 (i18n of
> multi-line advice messages, 2011-12-22) to produce such output:
>
> hint: some multi-line advice
> hint: prefixed with "hint: "
>
> The prefix is actually colored after 960786e761 (push: colorize errors,
> 2018-04-21) and each line has a suffix for resetting the color.
>
> The next commit will teach the same "prefix all the lines"-trick to the
> code that produces, e.g., "warning: "-messages. In preparation for that,
> extract the code for printing the individual lines and expose it through
> git-compat-util.h.
>
> Signed-off-by: Martin Ågren <martin.agren@gmail.com>
> ---
> I'm open for suggestions on the naming of `prefix_suffix_lines()`...