runtime(markdown): Fix folding of code blocks

Author: tpope

runtime/ftplugin/markdown.vim

@@ -1,7 +1,7 @@
 " Vim filetype plugin
 " Language:     Markdown
 " Maintainer:   Tim Pope <https://github.com/tpope/vim-markdown>
-" Last Change:  2022 Oct 13
+" Last Change:  2023 Dec 28
 
 if exists("b:did_ftplugin")
   finish
@@ -35,7 +35,7 @@ if !exists("g:no_plugin_maps") && !exists("g:no_markdown_maps")
 endif
 
 function! s:NotCodeBlock(lnum) abort
-  return synIDattr(synID(a:lnum, 1, 1), 'name') !=# 'markdownCode'
+  return synIDattr(synID(a:lnum, 1, 1), 'name') !=# 'markdownCodeBlock'
 endfunction
 
 function! MarkdownFold() abort