fix: 51 voa single title (#4639)

lib/routes/51voa/channel.js

@@ -139,7 +139,7 @@ module.exports = async (ctx) => {
             const single = {
                 pubDate: date($('div.Content>span.datetime').text()),
                 link: $('div.title h1').text(),
-                title: title,
+                title: $('div.title>h1').html(),
                 description: $('div.Content').html(),
                 category: ['study', 'English'],
             };