[UPDATE] add latest CS242 website (#784)

* [UPDATE] add new CS242 site (zh-cn)

* [UPDATE] add new CS242 site (en)

Author: Gravifer

docs/编程语言设计与分析/CS242.en.md

@@ -39,7 +39,7 @@ I personally feel that the assignments are difficult, but the gains are great. W
 
 ## Course Resources
 
-- Course Website: [https://stanford-cs242.github.io/f19/](https://stanford-cs242.github.io/f19/)
+- Course Website: [Latest](https://web.stanford.edu/class/cs242/) [2019 Fall](https://stanford-cs242.github.io/f19/)
 - Recordings: None, the main learning resources are the course notes and assignments
 - Textbooks: The first half of the course is based on the famous [TAPL](https://www.cis.upenn.edu/~bcpierce/tapl/), and the second half has no fixed textbook
 - Assignments: [Assignment Guide](https://stanford-cs242.github.io/f19/assignments/) and [Assignment Repository](https://github.com/stanford-cs242/f19-assignments)

docs/编程语言设计与分析/CS242.md

@@ -39,7 +39,7 @@ CS242是一门讲程序语言 (Programming Language, PL) 的课程，但不是
 
 ## 课程资源
 
-- 课程网站：[官网](https://stanford-cs242.github.io/f19/)
+- 课程网站：[官网](https://web.stanford.edu/class/cs242/) [2019秋](https://stanford-cs242.github.io/f19/)
 - 课程视频：无，主要学习途径是课程笔记和完成作业
 - 课程教材：前半部分是著名的[TAPL](https://www.cis.upenn.edu/~bcpierce/tapl/)，后半部分则无固定教材
 - 课程作业：[实验指导](https://stanford-cs242.github.io/f19/assignments/)与[作业仓库](https://github.com/stanford-cs242/f19-assignments)