clarify why absolute is tested & stripped here

file_prune also fails on absolute filenames now

IkiWiki/Plugin/editpage.pm

@@ -92,7 +92,7 @@ sub cgi_editpage ($$) {
 	# wiki_file_regexp.
 	my ($page)=$form->field('page')=~/$config{wiki_file_regexp}/;
 	$page=possibly_foolish_untaint($page);
-	my $absolute=($page =~ s#^/+##);
+	my $absolute=($page =~ s#^/+##); # absolute name used for force location
 	if (! defined $page || ! length $page ||
 	    file_pruned($page)) {
 		error(gettext("bad page name"));