Remove extra period.

Author: lizmat

S29-functions.pod

@@ -269,7 +269,7 @@ See C<Synopsis 17: Concurrency> for more details.
 Attempt to sleep for up to C<$for> seconds since the last time C<interval>
 was called in the current thread, or the parent thread.  Returns number of
 seconds actually slept.  Does not sleep at all the first time it is called,
-or if the specified number of seconds has already passed since the last call..
+or if the specified number of seconds has already passed since the last call.
 Implementations are obligated to support sub-second resolutions if that is
 at all possible.