Remove dependency on typing_extensions

[seddonym]

As suggested #278.

[codspeed-hq]

CodSpeed Performance Report

Merging #281 will not alter performance

_{Comparing remove-typing-extensions (faa23b7) with main (20e0439)}

Summary

✅ 26 untouched
⏩ 23 skipped¹

Footnotes

1. 23 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩