fix: Rust 'raw string' artifacts in generated doc comments

[samkearney]

This issue was seen when using Tsify's derive macros inside a declarative macro_rules! macro. For example:

use tsify::Tsify;

// Helper macro that adds derives
macro_rules! my_types {
    ($($decl:item)+) => {$(
        #[derive(Tsify)]
        $decl
    )+};
}

/// A comment
#[derive(Tsify)]
struct Direct {
    x: i32,
}

my_types! {
  /// A comment
  struct Macro {
      x: i32,
  }
}

fn main() {
    println!("{}", Direct::DECL);
    // /**
    //  * A comment
    //  */
    // export interface Direct { ... }

    println!("{}", Macro::DECL);
    // /**
    //  *r" A comment
    //  */
    // export interface Macro { ... }
}

In the declarative macro case, the generated TypeScript comments contain raw string literal syntax artifacts like r", r#", and "#.

It seems like when tokens pass through a declarative macro, the compiler may re-serialize string literals in doc attributes using raw string syntax (r"..." or r#"..."#). This then comes out in the source code representation that's produced by lit.to_string() in the extract_doc_comments function. Re-parsing the literal as a LitStr fixes the issue and removes the need to strip quotes later.

[siefkenj]

@samkearney Thanks for this fix! It looks like the test failures might be due to a change in wasmbindgen and not you...Would you be able to rebuild the test artifacts?

[samkearney]

@siefkenj sorry, looks like there were some more test failures lurking behind those initial ones - I should have time to take a look at that in the next day or two