[Tizen.Security.SecureRepository] Add missing documentation descriptions

src/Tizen.Security.SecureRepository/Tizen.Security.SecureRepository/Manager.cs

@@ -35,6 +35,7 @@ public class Manager
         /// </remarks>
         /// <param name="ownerId">Data owner's ID.</param>
         /// <param name="alias">Data alias.</param>
+        /// <returns>Full alias, a concatenation of owner ID and alias.</returns>
         static public string CreateFullAlias(string ownerId, string alias)
         {
             return ownerId + Manager.OwnerIdSeperator + alias;
@@ -46,6 +47,7 @@ static public string CreateFullAlias(string ownerId, string alias)
         /// </summary>
         /// <since_tizen> 3 </since_tizen>
         /// <param name="alias">Data alias, which is owned by system service.</param>
+        /// <returns>Full alias, a concatenation of system service's owner ID and alias.</returns>
         static public string CreateFullSystemAlias(string alias)
         {
             return Manager.CreateFullAlias(Manager.SystemOwnerId, alias);

src/Tizen.Security.SecureRepository/Tizen.Security.SecureRepository/Pkcs12.cs

@@ -41,6 +41,7 @@ public class Pkcs12
         /// </remarks>
         /// <param name="filePath">Path of the PKCS12 file to be loaded.</param>
         /// <param name="filePassword">Passphrase used to decrypt the PCKS12 file.</param>
+        /// <returns>Pkcs12 class instance.</returns>
         /// <exception cref="ArgumentNullException">Thrown when filePath is null.</exception>
         /// <exception cref="InvalidOperationException">
         /// Thrown when there's no existing file on <paramref name="filePath"/>.