style(): unify docs and spacing (#1448)

* typo(barcode-scanner): fixe circle lint error

* typo(docs):  Unified the documentations

In some plugins the typescript markup was missing.
I also unified the console.log string from console.log("hello") to console.log('Hello') so any plugin page look the same.

src/@ionic-native/plugins/flashlight/index.ts

@@ -17,7 +17,6 @@ import { Cordova, Plugin, IonicNativePlugin } from '@ionic-native/core';
  *
  * this.flashlight.switchOn();
  *
- *
  * ```
  */
 @Plugin({