Update styling-the-navigator.md

Some navBar button properties were marked as common by mistake.

docs/styling-the-navigator.md

   navBarBackgroundColor: '#f7f7f7', // change the background color of the nav bar (remembered across pushes)
 
   navBarButtonColor: '#007aff', // Change color of nav bar buttons (eg. the back button) (remembered across pushes)
-  navBarButtonFontSize: 20, // Change font size nav bar buttons (eg. the back button) (remembered across pushes)
-  navBarButtonFontWeight: '500', // Change font weight nav bar buttons (eg. the back button) (remembered across pushes)
-
-  navBarLeftButtonFontSize: 17, // Change font size of left nav bar button
-  navBarLeftButtonColor: 'red', // Change color of left nav bar button
-  navBarLeftButtonFontWeight: '400', // Change font weight of left nav bar button
-
-  navBarRightButtonFontSize: 17, // Change font size of right nav bar button
-  navBarRightButtonColor: 'blue', // Change color of right nav bar button
-  navBarRightButtonFontWeight: '600', // Change font weight of right nav bar button
 
   navBarHidden: false, // make the nav bar hidden
   navBarHideOnScroll: false, // make the nav bar hidden only after the user starts to scroll
   disabledBackGesture: false, // default: false. Disable the back gesture (swipe gesture) in order to pop the top screen. 
   screenBackgroundImageName: '<name of image in Images.xcassets>', // Optional. default screen background image.
   
+  navBarButtonFontSize: 20, // Change font size nav bar buttons (eg. the back button) (remembered across pushes)
+  navBarButtonFontWeight: '500', // Change font weight nav bar buttons (eg. the back button) (remembered across pushes)
+
+  navBarLeftButtonFontSize: 17, // Change font size of left nav bar button
+  navBarLeftButtonColor: 'red', // Change color of left nav bar button
+  navBarLeftButtonFontWeight: '400', // Change font weight of left nav bar button
+
+  navBarRightButtonFontSize: 17, // Change font size of right nav bar button
+  navBarRightButtonColor: 'blue', // Change color of right nav bar button
+  navBarRightButtonFontWeight: '600', // Change font weight of right nav bar button
+  
   // Android only
   navigationBarColor: '#000000', // change the background color of the bottom native navigation bar.
   navBarTitleTextCentered: true, // default: false. centers the title.