chore(native): drop "stable C API" from PyContextVar decls comment

Author: vlad-scherbich

src/native/contextvar.rs

@@ -2,10 +2,9 @@ use pyo3::ffi;
 use pyo3::prelude::*;
 use std::ffi::CString;
 
-// PyContextVar_New/_Get/_Set are absent from pyo3-ffi's stable/limited-API bindings
-// (Py_LIMITED_API), which is activated for Python 3.15+ via PYO3_USE_ABI3_FORWARD_COMPATIBILITY.
-// Declare the stable C API locally so this module builds either way. Context variables were
-// introduced in Python 3.7, so these symbols are available on every supported interpreter.
+// PyContextVar_* are public CPython C-API symbols (since 3.7), not Limited API.
+// pyo3-ffi omits them under Py_LIMITED_API. Local decls so this module builds
+// when that cfg is on.
 unsafe extern "C" {
     fn PyContextVar_New(
         name: *const std::os::raw::c_char,