Update TotpSecurityStampBasedTokenProvider.cs

Add line breaks before return statement.
Use string interpolation instead of string concatenation.
Hyphenate the documentation.

src/Identity/Extensions.Core/src/TotpSecurityStampBasedTokenProvider.cs

@@ -5,7 +5,7 @@ using System.Threading.Tasks;
 namespace Microsoft.AspNetCore.Identity
 {
     /// <summary>
-    /// Represents a token provider that generates time based codes using the user's security stamp.
+    /// Represents a token provider that generates time-based codes using the user's security stamp.
     /// </summary>
     /// <typeparam name="TUser">The type encapsulating a user.</typeparam>
     public abstract class TotpSecurityStampBasedTokenProvider<TUser> : IUserTwoFactorTokenProvider<TUser>
@@ -38,6 +38,7 @@ namespace Microsoft.AspNetCore.Identity
             }
             var token = await manager.CreateSecurityTokenAsync(user);
             var modifier = await GetUserModifierAsync(purpose, manager, user);
+
             return Rfc6238AuthenticationService.GenerateCode(token, modifier).ToString("D6", CultureInfo.InvariantCulture);
         }
 
@@ -67,6 +68,7 @@ namespace Microsoft.AspNetCore.Identity
             }
             var securityToken = await manager.CreateSecurityTokenAsync(user);
             var modifier = await GetUserModifierAsync(purpose, manager, user);
+
             return securityToken != null && Rfc6238AuthenticationService.ValidateCode(securityToken, code, modifier);
         }
 
@@ -87,11 +89,12 @@ namespace Microsoft.AspNetCore.Identity
                 throw new ArgumentNullException(nameof(manager));
             }
             var userId = await manager.GetUserIdAsync(user);
-            return "Totp:" + purpose + ":" + userId;
+
+            return $"{Totp}:{purpose}:{userId}";
         }
 
         /// <summary>
-        /// Returns a flag indicating whether the token provider can generate a token suitable for two factor authentication token for
+        /// Returns a flag indicating whether the token provider can generate a token suitable for two-factor authentication token for
         /// the specified <paramref name="user"/>.
         /// </summary>
         /// <param name="manager">The <see cref="UserManager{TUser}"/> that can be used to retrieve user properties.</param>
@@ -99,8 +102,8 @@ namespace Microsoft.AspNetCore.Identity
         /// <returns>
         /// The <see cref="Task"/> that represents the asynchronous operation, containing the a flag indicating if a two
         /// factor token could be generated by this provider for the specified <paramref name="user"/>.
-        /// The task will return true if a two factor authentication token could be generated, otherwise false.
+        /// The task will return true if a two-factor authentication token could be generated, otherwise false.
         /// </returns>
         public abstract Task<bool> CanGenerateTwoFactorTokenAsync(UserManager<TUser> manager, TUser user);
     }
-}
+}