Add missing info to DIAGNOSTICS

DIAGNOSTICS.md

@@ -1,5 +1,5 @@
 # Status and Diagnostics API
-A status API exists, which dumps some basic diagnostic and statistical information, as well as basic information about the underlying Raft node. Assuming rqlite is started with default settings, rqlite status is available like so:
+A status API exists, which dumps some basic diagnostic and statistical information, as well as basic information about the underlying Raft node. Assuming the rqlite node is started with default settings, node status is available like so:
 
 ```bash
 curl localhost:4001/status?pretty
@@ -9,3 +9,7 @@ The use of the URL param `pretty` is optional, and results in pretty-printed JSO
 
 ## expvar support
 rqlite also exports [expvar](http://godoc.org/pkg/expvar/) information. The standard, and some custom information, is exposed. This data can be retrieved like so:
+
+```bash
+curl localhost:4001/debug/vars
+```