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/core/ionic-native-plugin.ts

@@ -21,7 +21,7 @@ export class IonicNativePlugin {
   /**
    * Returns the original plugin object
    */
-  static getPlugin(): any {}
+  static getPlugin(): any { }
 
   /**
    * Returns the plugin's name