feat: Add LC 79 word search (azl397985856#98)

Author: snowan

README.en.md

@@ -148,6 +148,7 @@ The data structures mainly includes:
 - [0073.set-matrix-zeroes](./problems/73.set-matrix-zeroes.md )
 - [0075.sort-colors](./problems/75.sort-colors.md)
 - [0078.subsets](./problems/78.subsets.md)
+- [0079.word-search](./problems/79.word-search-en.md)
 - [0086.partition-list](./problems/86.partition-list.md)
 - [0090.subsets-ii](./problems/90.subsets-ii.md)
 - [0091.decode-ways](./problems/91.decode-ways.md)

README.md

@@ -167,6 +167,7 @@ leetcode 题解，记录自己的 leetcode 解题之路。
 - [0073.set-matrix-zeroes](./problems/73.set-matrix-zeroes.md )
 - [0075.sort-colors](./problems/75.sort-colors.md)
 - [0078.subsets](./problems/78.subsets.md)
+- [0079.word-search](./problems/79.word-search.md)
 - [0086.partition-list](./problems/86.partition-list.md)
 - [0090.subsets-ii](./problems/90.subsets-ii.md)
 - [0091.decode-ways](./problems/91.decode-ways.md)