Fix for strings with extra newlines/carriage returns

The \n escaping is working fine, but for HTML output that still has
weird returns, Javascript will take that as a newline and throw an
"Unterminated string literal" error in the browser-side. Removing \R
after the \n have been escaped solves the issue.

Thank you to bureado <https://github.com/bureado>, who authored this
change and commit.

lib/App/DuckPAN/Web.pm

@@ -113,7 +113,7 @@ sub request {
 						elsif ($rewrite->wrap_string_callback && $rewrite->callback) {
                             $body =~ s/"/\\"/g;
                             $body =~ s/\n/\\n/g;
-                            $body =~ s/\r//g;
+                            $body =~ s/\R//g;
 							$body = $rewrite->callback.'("'.$body.'");';
 						}
 						$response->code($res->code);