Fix bold

Author: mpalourdio

README.md

@@ -79,7 +79,7 @@ In your app.component.html, simply add:
 
 ## Customizing the spinner
 
-You can customize the **background-color**, the **spinner type**, the **debounce delay** (ie. after how many milliseconds the spinner will be visible, if needed), the **minimum duration** (ie. how many milliseconds should the spinner be visible at least), the **extra duration* (ie. how many extra milliseconds should the spinner be visible)):
+You can customize the **background-color**, the **spinner type**, the **debounce delay** (ie. after how many milliseconds the spinner will be visible, if needed), the **minimum duration** (ie. how many milliseconds should the spinner be visible at least), the **extra duration** (ie. how many extra milliseconds should the spinner be visible)):
 ```xml
 <ng-http-loader 
     [backgroundColor]="'#ff0000'"