[master] 3dfabb8b2 doc: Point out that the working directory (-n argument) is per instance

[Nils Goroll]

commit 3dfabb8b28d840bff01e945868469892f21d3b0c
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Mon Nov 4 10:17:48 2024 +0100

    doc: Point out that the working directory (-n argument) is per instance
    
    Motivated by https://github.com/varnishcache/pkg-varnish-cache/issues/178#issuecomment-2453792934

diff --git a/bin/varnishd/mgt/mgt_main.c b/bin/varnishd/mgt/mgt_main.c
index 8a9143285..a31ef0506 100644
--- a/bin/varnishd/mgt/mgt_main.c
+++ b/bin/varnishd/mgt/mgt_main.c
@@ -92,6 +92,8 @@ mgt_DumpOptions(void)
 	       "compiled VCLs etc.\n\n");
 	printf("  In performance critical applications, this directory "
 	       "should be on a RAM backed filesystem.\n\n");
+	printf("  When running multiple varnishd instances, separate "
+	       "directories need to be used.\n\n");
 	VIN_DumpDefaults();
 }