Fix: Typeface: var_with_undersore triggered syntax italic

autoload/vimwiki/u.vim

@@ -292,4 +292,8 @@ function! vimwiki#u#hi_typeface(dic) abort
     " -- Italic 3
     call vimwiki#u#hi_tag(u[0], u[1], 'VimwikiItalicBoldUnderline', '', 2)
   endfor
+
+  " Prevent var_with_underscore to trigger italic text
+  " -- See $VIMRUNTIME/syntax/markdown.vim
+  syn match VimwikiError "\w\@<=_\w\@="
 endfunction

syntax/vimwiki.vim

@@ -339,6 +339,7 @@ let s:syntax_dic = vimwiki#vars#get_syntaxlocal('dTypeface')
 call vimwiki#u#hi_typeface(s:syntax_dic)
 
 hi def link VimwikiMarkers Normal
+hi def link VimwikiError Normal
 
 hi def link VimwikiEqIn Number
 hi def link VimwikiEqInT VimwikiEqIn

syntax/vimwiki_markdown.vim

@@ -42,7 +42,6 @@ let s:markdown_syntax.dTypeface['bold_italic'] = [
       \ ['\S\@<=___\|___\S\@=', '\S\@<=___\|___\S\@='],
       \ ]
 
-
 " text: $ equation_inline $
 let s:markdown_syntax.rxEqIn = '\$[^$`]\+\$'
 let s:markdown_syntax.char_eqin = '\$'