Die on pod warnings also.

Helps catch errors like C<asdf

Fix comment;

t/pod-valid.t

@@ -4,7 +4,7 @@ use lib 'lib';
 
 =begin overview
 
-Insure any text that isn't a code example has a space after each comma.
+Insure any text that isn't a code example has valid POD6
 
 =end overview
 
@@ -22,15 +22,18 @@ if @*ARGS {
 
 plan +@files;
 
+my %data;
+
 sub test-it($job) {
-    ok !$job.exitcode, "{$job.command[*-1]} has valid Pod6"
+    my $file = $job.command[*-1];
+    ok !$job.exitcode && !%data{$file}, "$file has clean POD6"
 }
 
 my @jobs;
 for @files -> $file {
     my $p =  Proc::Async.new($*EXECUTABLE-NAME, '--doc', $file);
     $p.stdout.tap(-> $buf {});
-    $p.stderr.tap(-> $buf {});
+    $p.stderr.tap(-> $buf { %data{$file} = 1 });
     push @jobs: $p.start;
     if +@jobs > $max-jobs {
         test-it(await @jobs.shift);