Remove legacy triple slash directives

[jeromepochat]

I'm facing build issue when using RxDB from Angular project due to triple-slash directive usage in pouchdb-helper.d.ts.

Minimal project to reproduce issue

• packages.json

{
  "dependencies": {
    "rxdb": "^13.4.5"
  }
}

• main.ts

import { addPouchPlugin, getRxStoragePouch } from 'rxdb/plugins/pouchdb'

console.log("Hello world")

• tsconfig

{
  "compilerOptions": {
    "types": []
  }
}

Build command line

npm i && tsc

Build error

...
node_modules/@types/node/ts4.8/buffer.d.ts:97:14 - error TS2661: Cannot export 'Buffer'. Only local declarations can be exported from a module.

97     export { Buffer };
                ~~~~~~


Found 1 error in node_modules/@types/node/ts4.8/buffer.d.ts:97

[pubkey]

Thank you merged.