Need help for vimwiki with markdown syntax

[guruor]

I am using vimwiki with markdown syntax.
Have added below line in ftplugin->vimwiki.vim to override default commentstring(%%) for vimwiki:

set commentstring=<!--\ %s\ -->

This works well and gcc adds proper comment like this:

<!-- TODOs -->

But for code blocks also it uses the same commentstring, while in markdown file it works well.

My understanding is, this plugin determines the commentstring with help of tree-sitter so I even tried setting the markdown parser for vimwiki file, and now the vimwiki files are using markdown syntax but it didn't help.

Snippet used for overriding the vimwiki tree-sitter parser:

local ft_to_parser = require"nvim-treesitter.parsers".filetype_to_parsername
ft_to_parser.vimwiki = "markdown"

Note: Filetype for vimwiki files is vimwiki only, I don't want to change that, because if I change that I'll loose the mapping and functionalities defined by vimwiki pluggin.