Update PEP reference in future_rewritable_type_annotation.rs

[ericbn]

Summary

Documentation mentions:

PEP 563 enabled the use of a number of convenient type annotations, such as list[str] instead of List[str]

but it meant PEP 585 instead.

PEP 563 is the one defining from __future__ import annotations.

Test Plan

No automated test required, just verify that https://peps.python.org/pep-0585/ is the correct reference.

[codspeed-hq]

CodSpeed Performance Report

Merging #11985 will degrade performances by 4.81%

_{Comparing ericbn:patch-1 (4d78032) with main (519a278)}

Summary

❌ 1 regressions
✅ 29 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	ericbn:patch-1	Change
❌	linter/default-rules[pydantic/types.py]	1.8 ms	1.9 ms	-4.81%

[VascoSch92]

this should also been changed or?

[ericbn]

No, this reference is correct.

Lots of PEP involved here. :- )

[zanieb]

Thanks!