Update documentation for sealed types.

Author: bgrainger

docs/content/api/MySqlConnector/MySqlCommandBuilderType.md

@@ -5,7 +5,7 @@ title: MySqlCommandBuilder
 # MySqlCommandBuilder class
 
 ```csharp
-public class MySqlCommandBuilder : DbCommandBuilder
+public sealed class MySqlCommandBuilder : DbCommandBuilder
 ```
 
 ## Public Members

docs/content/api/MySqlConnector/MySqlConversionExceptionType.md

@@ -7,7 +7,7 @@ title: MySqlConversionException
 [`MySqlConversionException`](../MySqlConversionExceptionType/) is thrown when a MySQL value can't be converted to another type.
 
 ```csharp
-public class MySqlConversionException : Exception
+public sealed class MySqlConversionException : Exception
 ```
 
 ## See Also