Fix typos discovered by codespell

[cclauss]

Summary

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

Fix typos discovered by codespell - https://pypi.org/project/codespell

% codespell --ignore-words-list=asend,unkown --skip="*.json"

% codespell --ignore-words-list=asend,unkown --skip="*.json" --write-changes

• Fix typos discovered by codespell encode/httpx#3656

[codspeed-hq]

Merging this PR will not alter performance

✅ 7 untouched benchmarks

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_{Comparing cclauss:codespell (9362b55) with main (b4c5940)}