fix(setup): correct has_ext_modules method parameter name (#417)

## Summary

Fix the  method parameter name from  to  in  class.

## Root Cause

In  line 33:


The parameter should be to follow Python method conventions. This is
inconsistent with defined just above it on line 29, and with the parent
class .

While functionally equivalent (Python doesn't enforce parameter naming),
this:
- Confuses linters and type checkers (pylint R0201, mypy)
- Is inconsistent with the rest of the codebase
- Makes the code harder to read

## Test plan

- [x] Verify  still works
- [x] Verify wheel build process is unaffected

Co-authored-by: Test User <test@example.com>

Author: hobostay

setup.py

@@ -30,7 +30,7 @@ def is_pure(self) -> bool:
         """Return `False` because EnvPool ships extension modules."""
         return False
 
-    def has_ext_modules(foo) -> bool:
+    def has_ext_modules(self) -> bool:
         """Report that EnvPool has extension modules."""
         return True