Add references to TypeScript in documentation where appropriate, such
as in example bash commands and discussions of the file structure.
Add a new section to the Reading List with TypeScript resources.
Also update `.editorconfig` to support ".ts" files.
Fix part of #12000.
110 is what we enforce in Python code via our existing lint rules, and
120 is what we'd most realistically move the JS codebase to next.
Make supported IDEs and text editors keep a maximum line length of 110
characters for most code files.
I didn't add anything about the following extensions since they had
way too many different styles:
- .txt
- .conf
- .erb (saw tab, 2-spaced, 4-spaced and 8-spaced files around the codebase)
Fixes#3099.
Marco Burstein
Yago González
neiljp (Neil Pilgrim)
Diego Berrocal
Tommy Ip
Bojidar Marinov