[Rd] Typo fix for readBin.Rd

[Seth Falcon]

Hi, 

The man page for readBin has a small typo:

--- a/src/library/base/man/readBin.Rd
+++ b/src/library/base/man/readBin.Rd
@@ -58,7 +58,7 @@ writeBin(object, con, size = NA, endian 
 
   \code{readBin} and \code{writeBin} read and write C-style
   zero-terminated character strings.  Input strings are limited to 10000
-  characters.  \code{\link{readChar}} and \code{\code{writeChar}}
+  characters.  \code{\link{readChar}} and \code{\link{writeChar}}
   
   Handling \R's missing and special (\code{Inf}, \code{-Inf} and