[Rd] comment causes browser() to exit (PR#9063)

[timh at insightful.com]

I'm trying to step through some code using browser(),
executing one line at a time.
Unfortunately, whenever I execute a comment line, the browser exits.

I previously reported a similar problem with blank lines.

These problems are a strong incentive to write poor code 
-- uncommented code with no blank lines to improve readability --
so that I can use browser() without it exiting at inconvenient times.

Additional detail:  
(1) I'm running R inside emacs, with R in one buffer
and a file containing code in another, using a macro to copy and paste
a line at a time from the file to the R buffer.
(2) The browser() call is inside a function.  
Right now the lines I'm sending to the browser are not part of the function,
though usually they are.


--please do not edit the information below--

Version:
 platform = i386-pc-mingw32
 arch = i386
 os = mingw32
 system = i386, mingw32
 status = 
 major = 2
 minor = 3.1
 year = 2006
 month = 06
 day = 01
 svn rev = 38247
 language = R
 version.string = Version 2.3.1 (2006-06-01)

Windows XP Professional (build 2600) Service Pack 2.0

Locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

Search Path:
 .GlobalEnv, package:methods, package:stats, package:graphics, package:grDevices, package:utils, package:datasets, Autoloads, package:base