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/toast/index.ts

@@ -51,7 +51,7 @@ export interface ToastOptions {
  *
  * ...
  *
- * this.toast.show("I'm a toast", '5000', 'center').subscribe(
+ * this.toast.show('I'm a toast', '5000', 'center').subscribe(
  *   toast => {
  *     console.log(toast);
  *   }