feat: add [back to top] link next to each company

Author: hxu296

README.md

@@ -6,7 +6,7 @@ Curated lists of Leetcode questions group by companies, updated as of May, 2022.
 Shout out to fishercoder1534 for the awesome [Leetcode](https://github.com/fishercoder1534/Leetcode) repo for solutions.
 
 ## TODO
-- [] viz: add 'back to top' link next to each company
+- [o] viz: add 'back to top' link next to each company
 - [] data collection: extend scraper to collect both problem **type** and **company**
 - [] viz: add a new 'type' column for the problem frequency table
 - [] viz: add the 'major problem type' info for each company