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/background-geolocation/index.ts

@@ -448,13 +448,13 @@ export class BackgroundGeolocation extends IonicNativePlugin {
   /**
    * Display app settings to change permissions
    */
-  @Cordova({sync: true})
+  @Cordova({ sync: true })
   showAppSettings(): void { }
 
   /**
    * Display device location settings
    */
-  @Cordova({sync: true})
+  @Cordova({ sync: true })
   showLocationSettings(): void { }
 
   /**