[iOS] Large title text attributes (#2112)

* Add support for setting larget title text attributes

* Add documentation for setting large text attributes

See https://developer.apple.com/documentation/uikit/uinavigationbar/2919946-largetitletextattributes

docs/styling-the-navigator.md

   navBarRightButtonColor: 'blue', // Change color of right nav bar button
   navBarRightButtonFontWeight: '600', // Change font weight of right nav bar button
 
+  navBarLargeTextColor: '#000000', // change the text color of large titles
+  navBarLargeTextFontSize: 34, // change the font size of large titles
+  navBarLargeTextFontFamily: 'font-name', // Changes the large title font
+
   topBarShadowColor: 'blue' // Sets shadow of the navbar, Works only when topBarElevationShadowEnabled: true
   topBarShadowOpacity: 0.5, // Sets shadow opacity on the navbar, Works only when topBarElevationShadowEnabled: true
   topBarShadowOffset: 12, // Sets shadow offset on the navbar, Works only when topBarElevationShadowEnabled: true

ios/RCCViewController.m

     viewController.navigationController.navigationBar.barTintColor = nil;
   }
   
-  NSMutableDictionary *titleTextAttributes = [RCTHelpers textAttributesFromDictionary:self.navigatorStyle withPrefix:@"navBarText" baseFont:[UIFont boldSystemFontOfSize:17]];
+  NSMutableDictionary *titleTextAttributes = [RCTHelpers textAttributesFromDictionary:self.navigatorStyle
+                                                                           withPrefix:@"navBarText"
+                                                                             baseFont:[UIFont boldSystemFontOfSize:17]];
   [self.navigationController.navigationBar setTitleTextAttributes:titleTextAttributes];
+
+  if ([self.navigationController.navigationBar respondsToSelector:@selector(setLargeTitleTextAttributes:)]) {
+    // As defined in Apple's UI Design Resources: https://developer.apple.com/design/resources/
+    UIFont *largeBaseFont = [UIFont boldSystemFontOfSize:34];
+    NSMutableDictionary *largeTitleTextAttributes = [RCTHelpers textAttributesFromDictionary:self.navigatorStyle
+                                                                                  withPrefix:@"navBarLargeText"
+                                                                                    baseFont:largeBaseFont];
+    [self.navigationController.navigationBar setLargeTitleTextAttributes:largeTitleTextAttributes];
+  }
   
   NSMutableDictionary *navButtonTextAttributes = [RCTHelpers textAttributesFromDictionary:self.navigatorStyle withPrefix:@"navBarButton"];
   NSMutableDictionary *leftNavButtonTextAttributes = [RCTHelpers textAttributesFromDictionary:self.navigatorStyle withPrefix:@"navBarLeftButton"];