Corrected a misspelling in documentation comment (#128)

Author: rhtnr

src/IdentityServerAuthenticationOptions.cs

@@ -85,7 +85,7 @@ public class IdentityServerAuthenticationOptions : AuthenticationSchemeOptions
         public string CacheKeyPrefix { get; set; } = string.Empty;
 
         /// <summary>
-        /// Gets or sets the policay for the introspection discovery document.
+        /// Gets or sets the policy for the introspection discovery document.
         /// </summary>
         /// <value>
         /// The introspection discovery policy.
@@ -251,4 +251,4 @@ internal void ConfigureIntrospection(OAuth2IntrospectionOptions introspectionOpt
             };
         }
     }
-}
+}