Fix PR number in the NEWS.

Author: artemklevtsov

inst/NEWS.Rd

@@ -20,8 +20,9 @@
       \ghit{387}). 
       \item String constructors now set default UTF-8 encoding (Qiang Kou in
       \ghpr{529} fixing \ghit{263}).
-      \item Add variadic variants of the \code{RCPP_RETURN_VECTOR} and \code{RCPP_RETURN_MATRIX} macro when C++11 compiler used (Artem Klevtsov
-      in \ghpr{536} fixing \ghit{38}).
+      \item Add variadic variants of the \code{RCPP_RETURN_VECTOR} and
+      \code{RCPP_RETURN_MATRIX} macro when C++11 compiler used (Artem Klevtsov
+      in \ghpr{537} fixing \ghit{38}).
     }
     \item Changes in Rcpp unit tests
     \itemize{