VSCode: disable TypeScript language support (#5)
VSCode: disable TypeScript language support (#5)

## Summary:

Just getting TS features out of the way

Issue: "none"

## Test plan:

Open project in VSCode and note that it's not complaining about types only
being valid in a TypeScript project/file.

Author: jeremywiebe

Reviewers: kevinbarabash, jaredly, jeresig, jandrade, somewhatabstract

Required Reviewers:

Approved By: kevinbarabash

Checks:

Pull Request URL: https://github.com/Khan/kmath/pull/5
Khan/kmath