docs: fix 'dependancy' typo in SOCKS proxy docs

[mrchatam]

Summary

Fix typo in SOCKS proxy docs: dependancy → dependency.

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. (docs typo only — no code change)
• I've updated the documentation accordingly.

[mrchatam]

Closing — Test Suite fails on packaging/twine metadata ('2.5' is not a valid metadata version) unrelated to this docs typo; will avoid until upstream packaging CI is green.