add `typings` field to package.json

[KilianKilmister]

add "typings": "index.d.ts" field to package.json

without this many tools can not find it

[sindresorhus]

The TS docs say it can be left out if it's named index.d.ts. It's up to other tools to follow what TS supports.

[KilianKilmister]

The TS docs also says to put it in non the less. I find your justification very unreasonable

Also note that if your main declaration file is named index.d.ts and lives at the root of the package (next to index.js) you do not need to mark the "types" property, though it is advisable to do so.