Fixed typos in comments

Author: ckadluba

sample/AppConfigDemo/Program.cs

@@ -14,7 +14,7 @@ public static class Program
 
         public static void Main()
         {
-            // Legacy interace - do not use this anymore
+            // Legacy interface - do not use this anymore
             //Log.Logger = new LoggerConfiguration().WriteTo
             //    .MSSqlServer(
             //        connectionString: _connectionString,

sample/CombinedConfigDemo/Program.cs

@@ -23,7 +23,7 @@ public static void Main()
             var columnOptionsSection = configuration.GetSection("Serilog:ColumnOptions");
             var sinkOptionsSection = configuration.GetSection("Serilog:SinkOptions");
 
-            // Legacy interace - do not use this anymore
+            // Legacy interface - do not use this anymore
             //Log.Logger = new LoggerConfiguration()
             //    .WriteTo.MSSqlServer(
             //        connectionString: _connectionStringName,

sample/CustomLogEventFormatterDemo/Program.cs

@@ -19,7 +19,7 @@ public static void Main()
             var customFormatter = new FlatLogEventFormatter();
             var levelSwitch = new LoggingLevelSwitch();
 
-            // Legacy interace - do not use this anymore
+            // Legacy interface - do not use this anymore
             //Log.Logger = new LoggerConfiguration()
             //    .WriteTo.MSSqlServer(_connectionString,
             //        _tableName,