add parens to function names in the description

Author: jjallaire

DESCRIPTION

@@ -15,8 +15,8 @@ Authors@R: c(
     person(family = "Microsoft", role = "cph")
     )
 Description: High level functions for doing parallel programming with Rcpp.
-  For example, the parallelFor function can be used to convert the work of 
-  a standard serial "for" loop into a parallel one and the parallelReduce 
+  For example, the parallelFor() function can be used to convert the work of 
+  a standard serial "for" loop into a parallel one and the parallelReduce() 
   function can be used for accumulating aggregate or other values.
 Suggests: Rcpp, testthat
 SystemRequirements: GNU make, Windows: cmd.exe and cscript.exe