ios: fix compilation warnings

ios/sdk/src/JitsiMeet.h

 
 #pragma mak - This class is a singleton
 
-+ (instancetype)sharedInstance;
++ (instancetype _Nonnull)sharedInstance;
 
 #pragma mark - Methods that the App delegate must call
 
 -             (BOOL)application:(UIApplication *_Nonnull)application
   didFinishLaunchingWithOptions:(NSDictionary *_Nonnull)launchOptions;
 
--    (BOOL)application:(UIApplication * _Nonnull)application
-  continueUserActivity:(NSUserActivity * _Nonnull)userActivity
-    restorationHandler:(void (^ _Nullable)(NSArray * _Nullable))restorationHandler;
+-    (BOOL)application:(UIApplication *_Nonnull)application
+  continueUserActivity:(NSUserActivity *_Nonnull)userActivity
+    restorationHandler:(void (^_Nullable)(NSArray<id<UIUserActivityRestoring>> *_Nonnull))restorationHandler;
 
-- (BOOL)application:(UIApplication *)app
-            openURL:(NSURL *)url
-            options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options;
+- (BOOL)application:(UIApplication *_Nonnull)app
+            openURL:(NSURL *_Nonnull)url
+            options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *_Nonnull)options;
 
 #pragma mark - Utility methods
 
-- (JitsiMeetConferenceOptions *)getInitialConferenceOptions;
+- (JitsiMeetConferenceOptions *_Nonnull)getInitialConferenceOptions;
 
 @end

ios/sdk/src/JitsiMeet.m

 
 -    (BOOL)application:(UIApplication *)application
   continueUserActivity:(NSUserActivity *)userActivity
-    restorationHandler:(void (^)(NSArray *restorableObjects))restorationHandler {
+    restorationHandler:(void (^)(NSArray<id<UIUserActivityRestoring>> *))restorationHandler {
 
     JitsiMeetConferenceOptions *options = [self optionsFromUserActivity:userActivity];
 

ios/sdk/src/JitsiMeetConferenceOptions.h

 
 @property (nonatomic, readonly) BOOL welcomePageEnabled;
 
-+ (instancetype)fromBuilder:(void (^)(JitsiMeetConferenceOptionsBuilder *))initBlock;
-- (instancetype)init NS_UNAVAILABLE;
++ (instancetype _Nonnull)fromBuilder:(void (^_Nonnull)(JitsiMeetConferenceOptionsBuilder *_Nonnull))initBlock;
+- (instancetype _Nonnull)init NS_UNAVAILABLE;
 
 @end

ios/sdk/src/JitsiMeetView+Private.h

 
 @interface JitsiMeetView ()
 
-+ (instancetype)viewForExternalAPIScope:(NSString *)externalAPIScope;
++ (instancetype _Nullable)viewForExternalAPIScope:(NSString *_Nonnull)externalAPIScope;
 + (BOOL)setPropsInViews:(NSDictionary *_Nonnull)newProps;
 
 @end

ios/sdk/src/JitsiMeetView.h

  * is an already active conference it will be automatically left prior to
  * joining the new one.
  */
-- (void)join:(JitsiMeetConferenceOptions *)options;
+- (void)join:(JitsiMeetConferenceOptions *_Nullable)options;
 /**
  * Leaves the currently active conference.
  */