Update DIAGNOSTICS.md

doc/DIAGNOSTICS.md

@@ -8,7 +8,7 @@ curl localhost:4001/status?pretty
 The use of the URL param `pretty` is optional, and results in pretty-printed JSON responses.
 
 ## 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:
+rqlite also exports [expvar](http://godoc.org/pkg/expvar/) information. The standard expvar information, as well as some custom information, is exposed. This data can be retrieved like so:
 
 ```bash
 curl localhost:4001/debug/vars