normalized TOCs and titles in data cards
Oh right! I'd be in favor of still having the same TOC across the board, we can either leave it as is or add a `[More Info Needed]` `Contributions` Section wherever it's currently missing, wdyt? (I thought those were programmatically updated based on git history :D ) Merging for now to avoid conflict since there are so many changes but let's figure out the contributions section next ;) 
I started fixing some of the READMEs that were failing the tests introduced by @gchhablani but then realized that there were some consistent differences between earlier and newer versions of some of the titles (e.g. Data Splits vs Data Splits Sample Size, Supported Tasks vs Supported Tasks and Leaderboards). We also had different versions of the Table of Content

This PR normalizes all of them to the newer version