[Rd] Tiny documentation error for ?options (PR#8633)

[pinard@progiciels-bpi.ca]

Hi, people.  The output produced by "?options" contains:

     'expressions': sets a limit on the number of nested expressions
          that will be evaluated.  Valid values are 25...500000 with
          default 1000.  [...]

and a bit further down:

     The 'factory-fresh' default settings of some of these options are
       [...]
       'expressions'          '5000'

Is there a distinction between "default" and "factory-fresh default"?  
If not, then 1000 might be the correct value instead of 5000, as 1000 is 
contained in the list returned by R when given "options('expressions')".

--please do not edit the information below--

Version:
 platform = i686-pc-linux-gnu
 arch = i686
 os = linux-gnu
 system = i686, linux-gnu
 status = 
 major = 2
 minor = 2.1
 year = 2005
 month = 12
 day = 20
 svn rev = 36812
 language = R

Locale:
LC_CTYPE=fr_CA.UTF-8;LC_NUMERIC=C;LC_TIME=fr_CA.UTF-8;LC_COLLATE=fr_CA.UTF-8;LC_MONETARY=fr_CA.UTF-8;LC_MESSAGES=fr_CA.UTF-8;LC_PAPER=C;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C;LC_IDENTIFICATION=C

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