Change latex provider to luatex, closes #476

autoload/vimtex/syntax/p/pdfpages.vim

@@ -0,0 +1,33 @@
+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#pdfpages#load() abort " {{{1
+  if has_key(b:vimtex_syntax, 'pdfpages') | return | endif
+  let b:vimtex_syntax.pdfpages = 1
+
+  syntax match texInputFile /\\includepdf\>/
+        \ contains=texStatement
+        \ nextgroup=texInputFileOpt,texInputFileArg
+  syntax region texInputFileOpt
+        \ matchgroup=Delimiter
+        \ start="\[" end="\]"
+        \ contained
+        \ contains=texComment,@NoSpell
+        \ nextgroup=texInputFileArg
+  syntax region texInputFileArg
+        \ matchgroup=texInputCurlies
+        \ start="{" end="}"
+        \ contained
+        \ contains=texComment
+
+  highlight default link texInputFileArg texInputFile
+endfunction
+
+" }}}1
+
+endif