manual: Document the logging configuration

Change-Id: I66f5fe2e55c7e4cb6cc8ce09dcd8a636c717a5a0
diff --git a/doc/manuals/osmo-remsim-usermanual.adoc b/doc/manuals/osmo-remsim-usermanual.adoc
index 1679db2..32f173b 100644
--- a/doc/manuals/osmo-remsim-usermanual.adoc
+++ b/doc/manuals/osmo-remsim-usermanual.adoc
@@ -16,6 +16,8 @@
 
 include::{srcdir}/chapters/remsim-bankd.adoc[]
 
+include::{srcdir}/chapters/logging.adoc[]
+
 include::{srcdir}/chapters/rspro.adoc[]
 
 //include::./common/chapters/vty.adoc[]