feat(macros): support symbol-named methods in #[boa(class)]

[Yuvraj-cyborg]

Summary

This PR adds support for well-known symbol-keyed methods, statics, and accessors
in the #[boa(class)] macro. This allows builtins to declare them declaratively
instead of manually patching prototypes after registration.

Closes: #4688

---

What Changed

core/macros/src/class.rs

• Introduced a MethodName enum (String | Symbol) replacing the raw String name on:
  • Function
  • Accessor
  • ClassVisitor
• MethodName::to_key_tokens() now emits:
  • js_string!(...) for string keys
  • JsSymbol::iterator() (etc.) for symbol keys
• name_of() now:
  • Checks for #[boa(symbol = "...")] first
  • Validates against the 13 well-known symbol names
  • Falls through to #[boa(rename = "...")] or default rename scheme otherwise
• serialize_class_impl() now uses polymorphic key tokens for:
  • builder.method()
  • builder.static_method()
  • builder.accessor()
• match is handled via Ident::new_raw since it is a Rust keyword

core/macros/src/module.rs

• Updated Function::from_sig callsite to wrap the name in MethodName::String(...)

core/runtime/src/fetch/headers.rs

• Added #[boa(symbol = "iterator")] on JsHeaders
• Replaced the manual prototype patching TODO from Fix/headers iterable #4611 #4638

tests/macros/tests/class.rs

• Added Pair struct with:
  • #[boa(symbol = "toPrimitive")]
  • #[boa(symbol = "iterator")]
• Added boa_class_symbol_methods test covering:
  • Numeric coercion (+p)
  • Addition (p + 3)
  • Spread ([...p])
  • for...of

---

Accepted Symbol Names

The following well-known symbol names are supported:

• asyncIterator
• hasInstance
• isConcatSpreadable
• iterator
• match
• matchAll
• replace
• search
• species
• split
• toPrimitive
• toStringTag
• unscopables

Unknown names produce a compile-time error listing valid options.

---

Usage Example

#[boa_class]
impl MyType {
    #[boa(symbol = "iterator")]
    fn iter(&self, ctx: &mut Context) -> JsValue {
        /* ... */
    }

    #[boa(symbol = "toPrimitive")]
    fn to_prim(&self) -> i32 {
        42
    }
}

[Yuvraj-cyborg]

cc: @jedel1043

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,862	52,862	0
Passed	49,504	49,504	0
Ignored	2,262	2,262	0
Failed	1,096	1,096	0
Panics	0	0	0
Conformance	93.65%	93.65%	0.00%

[codecov]

Codecov Report

❌ Patch coverage is 21.73913% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.17%. Comparing base (6ddc2b4) to head (eebc6a4).
⚠️ Report is 710 commits behind head on main.

Files with missing lines	Patch %	Lines
core/macros/src/class.rs	0.00%	35 Missing ⚠️
core/macros/src/module.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4697      +/-   ##
==========================================
+ Coverage   47.24%   57.17%   +9.92%     
==========================================
  Files         476      550      +74     
  Lines       46892    60452   +13560     
==========================================
+ Hits        22154    34561   +12407     
- Misses      24738    25891    +1153     

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[Yuvraj-cyborg]

cc: @jedel1043

[jedel1043]

No need to CC me, just requesting a review already pings my notifications haha

[Yuvraj-cyborg]

No need to CC me, just requesting a review already pings my notifications haha

bad habit :)

[jedel1043]

Nice work! I have a suggestion to improve the maintainability of the code.