Highlight support for environments of package luacode

[RamonAbudAlcala]

When using LuaLaTeX one may load \usepackage{luacode} which provides a small arrange of commands and environments to handle lua code better than the native \directlua. When using these environment the contents are highlighted as if they were text. But it would be nice if these could be highlited as lua.

The commands and environments in question are (taken from the documentation): \luadirect \luaexec luacode (env) luacode* (env) \luastring \luastringN \luastringO

Note that lua highliting already happens if one uses \directlua