Small update

Author: jmprieur

articles/active-directory/develop/msal-net-token-cache-serialization.md

@@ -281,9 +281,19 @@ The [Microsoft.Identity.Web](https://github.com/AzureAD/microsoft-identity-web)
 | `AddSessionTokenCaches` | `TokenCacheProviders.Session` | The token cache is bound to the user session. This option isn't ideal if the ID token is too large because it contains too many claims as the cookie would be too large.
 | `AddDistributedTokenCaches` | `TokenCacheProviders.Distributed` | The token cache is an adapter against the ASP.NET Core `IDistributedCache` implementation, therefore enabling you to choose between a distributed memory cache, a Redis cache, a distributed NCache, or a SQL Server cache. For details about the `IDistributedCache` implementations, see https://docs.microsoft.com/aspnet/core/performance/caching/distributed#distributed-memory-cache.
 
+Simple case using the in-memory cache:
+
+```C#
+// or use a distributed Token Cache by adding
+    services.AddSignIn(Configuration);
+    services.AddWebAppCallsProtectedWebApi(Configuration, new string[] { scopesToRequest })
+            .AddInMemoryTokenCaches();
+```
+
+
 Examples of possible distributed caches:
 
-```CSharp
+```C#
 // or use a distributed Token Cache by adding
     services.AddSignIn(Configuration);
     services.AddWebAppCallsProtectedWebApi(Configuration, new string[] { scopesToRequest })