fix leetcode.cn change payload bug and fix typo in readme (#32)

Author: yihong0618

README.md

@@ -40,7 +40,7 @@ Great thanks to leetcode.com, a really awesome website!
 
 	Read help first                         $ leetcode help
 	Login with your leetcode account        $ leetcode user -l
-	Cookie login with cookie				$ leetcode user -c
+	Cookie login with cookie                $ leetcode user -c
 	Browse all questions                    $ leetcode list
 	Choose one question                     $ leetcode show 1 -g -l cpp
 	Coding it!

lib/plugins/leetcode.cn.js

@@ -97,12 +97,10 @@ plugin.getProblemsTitle = function(cb) {
       'query getQuestionTranslation($lang: String) {',
       '  translations: allAppliedQuestionTranslations(lang: $lang) {',
       '    title',
-      '    question {',
-      '      questionId',
+      '    questionId',
+      '    __typename',
       '    }',
-      '  }',
-      '}',
-      ''
+      '}'
     ].join('\n'),
     variables:     {},
     operationName: 'getQuestionTranslation'
@@ -116,7 +114,7 @@ plugin.getProblemsTitle = function(cb) {
 
     const titles = [];
     body.data.translations.forEach(function(x) {
-      titles[x.question.questionId] = x.title;
+      titles[x.questionId] = x.title;
     });
 
     return cb(null, titles);