remove trailing whitespace

Author: coke

doc/Language/haskell-to-p6.pod6

@@ -381,10 +381,10 @@ And now in Perl6 :
     =begin code
     # using `if` and `for`
     my @evens = ($_ if $_ %% 2 for ^100);
-    
+
     # using gather/take to build a Seq
     my $evens = gather for ^100 { take $_ if $_ %% 2 };
-    
+
     # using gather/take to build an Array
     my @evens = gather for ^100 { take $_ if $_ %% 2 };
     =end code