Remove language count from readme

[Richienb]

It is inconvenient to maintain the language count in the readme because after merging one PR that adds a language, all other PRs will be out of date.

As an alternative, we could launch a static page that auto-deploys with each language + updated language count + extras. (#1543, #317, #1296, #316, #293)

[MrBrain295]

Idrc the only good alternative I can think of is having the readme update script run on every commit with a gh action or something like that.