Close unclosed X<> token

Author: zoffixznet

doc/Language/containers.pod6

@@ -123,7 +123,7 @@ changes the contents of the other.
 You've seen this situation before: it is exactly what happened with the
 signature parameter marked as C<is rw>.
 
-X<|\,container binding
+X<|\,container binding>
 Sigilless variables also bind by default and so do parameters with the trait C<is raw>.
 
     my $a = 42;