bug#46859: 28.0.50; [PATCH]: Add option to truncate long lines in xref.el

[Juri Linkov]

> The added functionality is created to not kick in before a certain
> threshold, where 500 columns seems reasonably long. Anything above that
> will be truncated, but xref will still show that there was a hit.
>
> I'm sure the patch can be improved, so please, don't hesitate to tell
> me.
>
> I consider this a great improvement, and I hope you will to§

I've customized 'xref-search-program-alist' that defines ripgrep
command line to contain additional options:

  -M 500 --max-columns-preview

that truncates long lines of ripgrep output
after we discussed this in https://debbugs.gnu.org/44983

But maybe your new option would be easier to customize.