Highlight LaTeX commands in list continuation

This commit is an extension of the previous commit 45d5862.
In a multi-line list item (i.e. pandocListItemContinuation), LaTeX
commands should be highlighted as well.

Author: wookayin

syntax/pandoc.vim

@@ -427,7 +427,7 @@ endif
 syn match pandocListItemBullet /^(\?.\{-}[.)]/ contained containedin=pandocListItem
 syn match pandocListItemBulletId /\(\d\+\|\l\|\#\|@.\{-}\|x\=l\=\(i\{,3}[vx]\=\)\{,3}c\{,3}\)/ contained containedin=pandocListItemBullet
 
-syn match pandocListItemContinuation /^\s\+\([-+*]\s\+\|(\?.\+[).]\)\@<!\([[:alpha:]ñäëïöüáéíóúàèìòùłßÄËÏÖÜÁÉÍÓÚÀÈÌÒÙŁß_"[]\|\*\S\)\@=.*$/ nextgroup=pandocLaTeXMathBlock,pandocLaTeXInlineMath,pandocDelimitedCodeBlock,pandocListItemContinuation,pandocListItem contains=@Spell,pandocEmphasis,pandocStrong,pandocNoFormatted,pandocStrikeout,pandocSubscript,pandocSuperscript,pandocStrongEmphasis,pandocStrongEmphasis,pandocPCite,pandocICite,pandocCiteKey,pandocReferenceLabel,pandocReferenceURL,pandocLaTeXMathBlock,pandocLaTeXInlineMath,pandocAutomaticLink contained skipempty display 
+syn match pandocListItemContinuation /^\s\+\([-+*]\s\+\|(\?.\+[).]\)\@<!\([[:alpha:]ñäëïöüáéíóúàèìòùłßÄËÏÖÜÁÉÍÓÚÀÈÌÒÙŁß_"[]\|\*\S\)\@=.*$/ nextgroup=pandocLaTeXMathBlock,pandocLaTeXInlineMath,pandocDelimitedCodeBlock,pandocListItemContinuation,pandocListItem contains=@Spell,pandocEmphasis,pandocStrong,pandocNoFormatted,pandocStrikeout,pandocSubscript,pandocSuperscript,pandocStrongEmphasis,pandocStrongEmphasis,pandocPCite,pandocICite,pandocCiteKey,pandocReferenceLabel,pandocReferenceURL,pandocLaTeXCommand,pandocLaTeXMathBlock,pandocLaTeXInlineMath,pandocAutomaticLink contained skipempty display 
 " }}}
 " Definitions: {{{2
 "