Sync syntax from start

Syncing by block start patterns didn't restore states inside the
block, so syntax computed before a line was displayed, e.g. by
GetVueTag() or indent after jumping in a file, missed regions like a
multi-line css rule. This replaces the one-line block fix in the
previous commit.

Parsing from start takes ~190ms once for jumping to the end of a
6500-line file, and states are cached after that.

syntax/vue.vim

@@ -124,12 +124,6 @@ function! s:SetSyntax(block, syntax, has_lang)
         \.' end=+'.end.'+'
         \.' keepend contains='.syntax_group.', vueTag'
 
-  " Don't sync to a block ending on the same line, like
-  " <style>p { color: red; }</style>
-  let sync_start = start.'\(.*'.end_tag.'\)\@!'
-  execute 'syntax sync match vueSync groupthere '.name.' +'.sync_start.'+'
-  execute 'syntax sync match vueSync groupthere NONE +'.end.'+'
-
   " Block like <script src="...">...</script>
   let oneline = start.'.*'.end_tag
   execute 'syntax match '.name.' fold '
@@ -138,7 +132,10 @@ function! s:SetSyntax(block, syntax, has_lang)
 endfunction
 
 function! s:SetBlockSyntax(config_syntax)
+  " Parse from start, as syncing by block start doesn't restore states inside
+  " the block like a multi-line css rule
   syntax sync clear
+  syntax sync fromstart
 
   for [block, syntax] in items(a:config_syntax)
     let type = type(syntax)