doc: More cross-references; Expand overview slightly

Change-Id: Ic290627ec2512a2b59cb9d81704b9cec4d14ccf4
diff --git a/doc/manuals/chapters/remsim-server.adoc b/doc/manuals/chapters/remsim-server.adoc
index 5215b54..304a7f3 100644
--- a/doc/manuals/chapters/remsim-server.adoc
+++ b/doc/manuals/chapters/remsim-server.adoc
@@ -1,3 +1,4 @@
+[[remsim-server]]
 == osmo-remsim-server
 
 === Running
@@ -18,6 +19,7 @@
 verbosity is not yet configurable.  However, as the libosmocore logging
 framework is used, extending this is an easy modification.
 
+[[rsres]]
 === RESTful/JSON Web API
 
 `osmo-remsim-server` provides a RESTful/JSON WEB API for application logic