Documentation: update git configuration for Link: tag

The latest version of git (2.41.0) changed the spelling
of Message-Id to Message-ID. Adjust the perl script here
to accept both spellings.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230619115533.981f6abaca01.I1960c39b1d61e8514afcef4806a450a209133187@changeid

Documentation/maintainer/configure-git.rst

@@ -56,7 +56,7 @@ by adding the following hook into your git:
 	$ cat >.git/hooks/applypatch-msg <<'EOF'
 	#!/bin/sh
 	. git-sh-setup
-	perl -pi -e 's|^Message-Id:\s*<?([^>]+)>?$|Link: https://lore.kernel.org/r/$1|g;' "$1"
+	perl -pi -e 's|^Message-I[dD]:\s*<?([^>]+)>?$|Link: https://lore.kernel.org/r/$1|g;' "$1"
 	test -x "$GIT_DIR/hooks/commit-msg" &&
 		exec "$GIT_DIR/hooks/commit-msg" ${1+"$@"}
 	: