rebase: note preserve merges may be a pull config option

The `--preserve-merges` option was removed by v2.34.0. However
users may not be aware that it is also a Pull configuration option,
which is still offered by major IDE vendors such as Visual Studio.

Extend the `--preserve-merges` die message to also direct users to
the possible use of the `preserve` option in the `pull.rebase` config.
This is an additional 'belt and braces' information statement.

Signed-off-by: Philip Oakley <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: PhilipOakley

builtin/rebase.c

@@ -1207,7 +1207,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			     builtin_rebase_usage, 0);
 
 	if (preserve_merges_selected)
-		die(_("--preserve-merges was replaced by --rebase-merges"));
+		die(_("--preserve-merges was replaced by --rebase-merges\n"
+			"Note: Your `pull.rebase` configuration may also be  set to 'preserve',\n"
+			"which is no longer supported; use 'merges' instead"));
 
 	if (action != ACTION_NONE && total_argc != 2) {
 		usage_with_options(builtin_rebase_usage,