Change the protocol name

Follow the Objc naming convention to name the protocol the same as the object.

GoogleSignIn/Sources/GIDKeychainHandlling/GIDKeychainHandlling.h → GoogleSignIn/Sources/GIDKeychainHandler/GIDKeychainHandler.h

@@ -20,7 +20,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-@protocol GIDKeychainHandlling <NSObject>
+@protocol GIDKeychainHandler <NSObject>
 
 - (OIDAuthState *)loadAuthState;
 

GoogleSignIn/Sources/GIDKeychainHandlling/GIDKeychainHandler.h → GoogleSignIn/Sources/GIDKeychainHandler/Implementations/GIDKeychainHandler.h

@@ -16,11 +16,11 @@
 
 #import <Foundation/Foundation.h>
 
-#import "GoogleSignIn/Sources/GIDKeychainHandlling/GIDKeychainHandlling.h"
+#import "GoogleSignIn/Sources/GIDKeychainHandler/GIDKeychainHandler.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
-@interface GIDKeychainHandler : NSObject<GIDKeychainHandlling>
+@interface GIDKeychainHandler : NSObject<GIDKeychainHandler>
 @end
 
 NS_ASSUME_NONNULL_END

GoogleSignIn/Sources/GIDKeychainHandlling/GIDKeychainHandler.m → GoogleSignIn/Sources/GIDKeychainHandler/Implementations/GIDKeychainHandler.m

@@ -1,4 +1,4 @@
-#import "GoogleSignIn/Sources/GIDKeychainHandlling/GIDKeychainHandler.h"
+#import "GoogleSignIn/Sources/GIDKeychainHandler/Implementations/GIDKeychainHandler.h"
 
 #ifdef SWIFT_PACKAGE
 @import AppAuth;
@@ -8,7 +8,6 @@
 #import <GTMAppAuth/GTMAppAuth.h>
 #endif
 
-// Keychain constants for saving state in the authentication flow.
 static NSString *const kGTMAppAuthKeychainName = @"auth";
 
 NS_ASSUME_NONNULL_BEGIN