Fix typo.

git-svn-id: https://svn.r-project.org/R/trunk@88375 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: kalibera

src/library/parallel/man/unix/children.Rd

@@ -90,7 +90,7 @@ mckill(process, signal = 2L)
   if the child no longer exists (no children at all for
   \code{readChildren}).
 
-  \code{selectChildren} returns \code{TRUE} is the timeout was reached,
+  \code{selectChildren} returns \code{TRUE} if the timeout was reached,
   \code{FALSE} if an error occurred (e.g., if the master process was
   interrupted) or an integer vector of process IDs with children that
   have data available, or \code{NULL} if there are no children.