Support braces {} to wrap the state bodies in Blocks

[Saltsmart]

In some earlier packages such as algorithmic, the statement in blocks could be wrapped in braces, like:

\FOR{\(k=1,\ldots,n\)}
{
    \STATE{Some statement}
}
\ENDFOR

Such braces {} are very useful for the document formatter (such as the Latex extension in VSCode) to get pretty indents.
However this will cause error for algpseudocodex package.

We hope this could be enhanced♥!