Change latex provider to luatex, closes #476

autoload/vimtex/syntax/p/luacode.vim

@@ -0,0 +1,31 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#syntax#p#luacode#load() abort " {{{1
+  if has_key(b:vimtex_syntax, 'luacode') | return | endif
+  let b:vimtex_syntax.luacode = 1
+
+  call vimtex#syntax#misc#include('lua')
+  call vimtex#syntax#misc#add_to_section_clusters('texZoneLua')
+  syntax region texZoneLua
+        \ start='\\begin{luacode\*\?}'rs=s
+        \ end='\\end{luacode\*\?}'re=e
+        \ keepend
+        \ transparent
+        \ contains=texBeginEnd,@vimtex_nested_lua
+  syntax match texStatement '\\\(directlua\|luadirect\)' nextgroup=texZoneLuaArg
+  syntax region texZoneLuaArg matchgroup=Delimiter
+        \ start='{'
+        \ end='}'
+        \ contained
+        \ contains=@vimtex_nested_lua
+endfunction
+
+" }}}1
+
+endif