Investigate how to hide lines in rendered code snippets

[cmichi]

The Idea

I would love to see code testing of our Rust code examples. This should be analog to how it works for Rust doc tests.

Reminder: In Rust comments, code snippets can be included like this:

/// ```
/// # <ink_ir::ItemImpl as TryFrom<syn::ItemImpl>>::try_from(syn::parse_quote! {
/// impl MyStorage {
///     #[ink(constructor)]
///     pub fn my_constructor() -> Self {
///         // constructor implementation
///         unimplemented!()
///     }
/// }
/// # }).unwrap();
/// ```

In the HTML-generated documentation the lines prefixed with # won't show up. But if you execute cargo test --doc the entire code snippet will be compiled, including the # prefixed lines.

We need something along those lines for use.ink.

ToDo

docusaurus uses prism.js for rendering code into HTML.

• Check if that tool supports hiding lines. I had briefly checked and didn't find anything. Might have overlooked it though.
• If it does not, create a PR for it to add this feature.

Follow-ups

This is not part of this ticket, but once we have the hide-lines feature for code we can:

• Ask Parity's OpsTooling to create a tool that extracts this code and compiles it.
• Integrate this tool into our CI.
• Add surrounding code to existing code snippets, so that they compile.