bug#44409: Example in manual no longer works

[積丹尼 Dan Jacobson]

(info "(emacs) Grep Searching") Says

   For instance, you can chain ‘grep’ commands, like this: ...

But the example it then gives is for older emacs versions.

Newer emacs versions' grep string contains "--null" (proof: try
$ emacs -f grep
) which will cause the example to fail.

How can one rewrite the example to work with newer emacs versions?