fix(lsp): E403 if doc contains multiple codeblocks #24458

Problem:
Content that has codeblocks with different languages, results in
multiple calls to:
    syntax include vim syntax/vim.vim
which raises error:
    E403: syntax sync: line continuations pattern specified twice
Before ba8f19ebb6, this was avoided by
using pcall() to ignore the error.

Solution:
Restore the use of pcall() to ignore the error.
We plan to replace this logic with a treesitter approach, so this is
good enough for now.

Fix #24431

runtime/lua/vim/lsp/util.lua

@@ -1466,7 +1466,7 @@ function M.stylize_markdown(bufnr, contents, opts)
       if #api.nvim_get_runtime_file(('syntax/%s.vim'):format(ft), true) == 0 then
         return
       end
-      vim.cmd(string.format('syntax include %s syntax/%s.vim', lang, ft))
+      pcall(vim.cmd, string.format('syntax include %s syntax/%s.vim', lang, ft))
       langs[lang] = true
     end
     vim.cmd(