Support language attribute in code element

[thibauult]

As a bot developer, I want to set the langage attribute from my \ block, so that the code I is highlighted correctly according to the programming language I am sending

MessageML example:

<messageML>

  <code langage="java">
    public void someMethod(String someAttribute) {
      System.out.println("This is a code block");
      System.out.println("Value of Attribute:" + someAttribute);
    }
  </code>

</messageML>

PresentationML result:

<div data-format="PresentationML" data-version="2.0"> 

  <code data-langage="java">
    public void someMethod(String someAttribute) {
      System.out.println("This is a code block");
      System.out.println("Value of Attribute:" + someAttribute);
    }
  </code>

</div>

For now the list of supported langages is:

• plaintext
• c
• cpp
• csharp
• css
• html
• java
• js
• jsx
• php
• python
• r
• typescript
• tsx

We need to check the langage key.