feat: support nested (injected) code blocks

[numToStr]

This PR fixes commenting in nested (injected) code blocks. Like in markdown you can have multiple code blocks and those code blocks can also have injected languages for example markdown -> vue -> css/js

Before

<style>
body {
    <!-- color: red; -->
}
</style>

<script>
while (true) {
    <!-- console.log("neovim is awesome!"); -->
}
</script>

After

<style>
body {
    /* color: red; */
}
</style>

<script>
while (true) {
    // console.log("neovim is awesome!");
}
</script>

---

Closes #137