bug#59888: [PATCH] Add 'grep-use-headings'

[Juri Linkov]

> There is still an issue I'm aware of: if one saves a grep buffer to a
> file and later opens the file, the headings are inserted a second time.
> I've tried a bit to display the headings only using text display
> properties (instead of inserting the actual text into the buffer), but
> wasn't successful so far.  Other, less elegant solutions are possible
> (e.g. deleting all headings either when saving or when reading again the
> file).

This reminds a similar problem that the file etc/grep.txt
can't be edited in grep-mode because then it will lose
all grep-filtered escape sequences on saving.