[Feature Request]: Add support for custom wrapper

[rytswd]

🔮 Relevant Command

importer update, importer generate

🗂 Language Type

Markdown

🔎 Request Details

When importing a code snippet from real code base into markdown, we should allow adding an extra wrapper such as code block (e.g. ```).

This may be useful for files other than markdown, but it can start with adding such support for markdown to begin with.

This is likely going to be an Importer Marker Option, and can be something like:

<!-- == imptr: test / begin from: ./some-code.go#1~ wrap: go == -->
<!-- == imptr: test / end == -->

And end up with something like (could not write as is here)

It is arguable if wrap is the best word to be used here, though...