Text input: Makdown support & UI enhancement

We like **styles** when *they* are **useful** ! * UI enhancement : Currently the placement of the button to validate a texfield is not super optimal, by placing it below the block, the rendering would be more pleasant and leave more comfort for the input * **Small Makdown support**: For long messages such as support tickets, users may need to put minimal formatting in their message and especially preserve the formatting of the code using the ``` ``` tags