Fixed some typos; mentioning internal debugger and RStudio.

documentation/debugging.md

 # Introduction
 
-Since FastR is implemented atop the Truffle framework, it also supports debugging of applications using NetBeans.
+Since FastR is implemented atop the Truffle framework, it supports debugging of applications using NetBeans.
 This is a very convenient and more powerful way for debugging compared to R's browser function.
+However, FastR also implements the internal debugging functions `browse`, `trace`, and so on.
+Unfortunately, FastR cannot support the RStudio debugger since it depends on GnuR's implementation.
 
 This section describes how to debug R applications using NetBeans.
 
 # Pre-Requisites
 
-* A recent NetBeans IDE (e.g. nightly build).
+* A recent NetBeans IDE (e.g. nightly build from http://bits.netbeans.org/download/trunk/nightly/latest/zip/).
 * The _Truffle Debugging Support_ Plugin for NetBeans.  
   Install this by starting NetBeans and selecting `Tools > Plugins > Available Plugins > Truffle Debugging Support`
 
@@ -25,12 +27,12 @@ This section describes how to debug R applications using NetBeans.
 `bin/R --J @-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000`
 
 3. Run your application.  
-   There are many ways to run your R application. The simplest one is using `source(file.R)`.
+   There are many ways to run your R application. The simplest one is using `source("file.R")`.
 
 # Additional Features
 
-The NetBeans debugger is source-location-based meaning that it assumes every source of an applicates resides somehwere in a source file.  
-However, R applications often run deserialized code or the code is created somehow else.
+The NetBeans debugger is source-location-based meaning that it assumes every source of an application resides somewhere in a source file.  
+However, R applications often run deserialized code or the code is created in some other way.
 
 In order to be still able to use the NetBeans debugger for such source, you first need to generate a temporary source file using a FastR builtin function.